In this continuing series, we round up some of our favorite new applications for smartphones each month, specifically for iPhone and Android devices. This spring edition is one of the longest lists yet - there have been a number of incredible new launches to highlight this past month. (And yes, we know it's May already, these things take time). As a bonus just for this month, we've added a section for new iPad and Honeycomb apps, too.

As always, feel free to share your favorite apps in the comments!

Both (iPhone and Android)

Fring: Not new, but a new release for both iPhone, Android and Nokia lets users make free group video calls with up to four friends. (Free, multiple app stores)

Trapcall: Available for iPhone, Android and BlackBerry, this call screening/call recording/call blocking app lets you see who's calling, even when the number is blocked, plus blacklist callers, record calls and more. Ethical questions aside (how is it unblocking numbers if not by violating user privacy somehow?), it's an app we know many will want. (Free app, service plans at $4.95/month+, multiple app stores)

Eventjot: This group photo-sharing app is almost exactly like Color, except that it doesn't use GPS to connect strangers. Instead, it's meant to be used with friends attending the same event. Hey, it's big in Japan. (Free, multiple app stores)

iPhone

MealSnap: An ingenious app that lets you take a picture of your food to determine how many calories are in it. The app doesn't always get things right of course, despite the human assistance on the backend - it thought my "Healthy Request" soup had over 1,000 calories! But it does well when it can see a picture with a brand logo on it, we've found. ($2.99, iTunes)

Tweetbot: A beautiful new Twitter iPhone app with all the standard features, but with an improved and efficient design. Our coverage. ($1.99, iTunes)

TweetDeck: Not a new app per se, but a complete "re-imagining" makes this 2.0 redesign feel brand-new. The app still offers columns, but adds support for Twitlonger competitor Deck.ly and more. Our coverage. (Free, iTunes)

Photosynth: This iOS app lets you stitch together multiple images to create a 360 degree panoramic photo. You can then share the photo back to Facebook or post it to Bing Maps. Our coverage. (Free, iTunes)

Fahrenheit: This new weather app for iPhone actually puts the current temperature on your home screen. About time! (Also, thanks.) ($0.99, iTunes)

RockMelt: The social Web browser becomes the social mobile browser with this app, which provides instant notifications from Twitter, Facebook and other favorite sites, social sharing features, a "read later" option for saving content and more. (Free, iTunes)

Zwapp: This new app lets you find and share the best new mobile apps with your friends, and like and comment on apps others shared with you. (Free, iTunes)

Cardcloud: This business card replacement app lets you share your Web-based social cards with anyone directly through the phone itself or via email. Our coverage. (Free, iTunes)

Silent Film Director: This app lets you turn your iPhone videos into old-timey black-and-white silent films from the 20's or even home videos from the 60's or 70's. Our coverage. ($1.99, iTunes)

Photo Lapse: This app lets you take time-lapsed photos by allowing you to snap a new photo every few minutes. Set it on on the window sill and watch your flowers grow or watch a construction project complete. ($1.99, iTunes)

Photofeed by Pixable: This new app aggregates your friends' photos from several popular online services, including Facebook, Flickr, Instagram and others. (Free, iTunes)

Cartoonatic: This iPhone app lets you record videos with cartoon effects. (Free, iTunes)

Atari's Greatest Hits: Flashback time! Atari delivers retro gaming with over 100 Classic titles including 92 Atari 2600 Games and 18 Classic Atari Arcade Games. (Free, iTunes)

MessageParty: This older app recently changed from group chat to geo-blogging. Posts are tied to locations, making it sort of like a standalone version of Foursquare's tips mixed with Twitter or a location-based Tumblr. We're not sure, actually, but cool concept. (Free, iTunes)

Huddl: A free group messaging app that lets you share photos and send messages to private groups. (Free, iTunes)

8tracks: Music discovery service which lets friends share mixes with each other is now available on iPhone. As you listen, you can favorite individual tracks or playlists and then go purchase the songs on iTunes. TechCrunch has the review. (Free, iTunes)

MapOmatic: This map app not only gives you directions, it gives you ideas. The app shows you which spots your friends checked into in the past via Foursquare and Facebook. Robert Scoble has the review. (Free, iTunes)

iAd Gallery: If you're not in the industry, this may be of no interest, but for those who are, Apple's own iAd Gallery offers a unique way to browse through the latest iAd campaigns, while also learning about the ads and the agencies behind them. (Free, iTunes)

Fotopedia Paris: Tour the City of Lights virtually, from your iPhone (or iPad) thanks to a collection of over 4,000 photos of art, architecture, cafes, castles, fashion, history, shops and street life. Or plan your upcoming trip to Paris with the app's "Trip Builder" function instead. (Free, iTunes)

Guardly: A new iPhone app designed to keep you safe, Guardly lets you quickly contact your own personal safety network (any number of people you specify) via voice, SMS or email, and/or 911. Our coverage. (Free, iTunes)

Squrl: This app is an Airplay-enabled video curation tool that lets you organize videos from multiple sources, including Netflix, Hulu, YouTube, Vimeo, TED and more. Robert Scoble has the review. (Free, iTunes)

Trimensional: Seriously cool, this iPhone app lets you scan and then print a 3D model of your face. Yes, your face! Unfortunately, app requires a 3D printer. Oh well. If you don't have one, at least you can enjoy the 3D modeling the app provides. Our coverage. ($0.99, iTunes).

PIM (Parking in Motion): This real-time parking information app lets you find, reserve and even pay for parking spots from your phone. The app includes parking info from the top 300+ cities in the U.S, top 50+ cities in Canada and the top 200+ cities in Europe. (Free, iTunes)

Remember It: This new iPhone app lets you create geo-fences of either 50, 200 or 500 feet from a given location so that when you leave the area, your phone will alert you with a signal or song. Never forget to pay your bar tab again! Our coverage. ($0.99, iTunes)

Social Questions: An unofficial, but officially sanctioned app for Q&A site Quora, this app lets you browse the website, plus view your profile, your inbox and your notifications.

ZoomReader: This iPhone app lets you magnify printed text by taking a picture of it. It then converts the text using OCR technology. Text can be read back to you with a natural-sounding voice. Really pricey, though, but works. ($19.99, iTunes).

Android

Viewdle SocialCamera: This app (still in beta) lets you tag your friends in your mobile photo and then share directly with Facebook, Flickr, MMS or email. The built-in facial recognition will learn your friends' faces in order to automatically tag them in future photos. (Free, Android Market)

Google Docs: An official app for Google Dcos lets you create, view, share and upload documents. You can also take a photo of printed text and convert it to a Google Doc. Our coverage. (Free, Android Market)

CNN App for Android Phones: This app brings the latest news, live video and iReport to your Android phone. (Free, Android Market)

Dock4Droid: This is a Mac-like task manager for Android. App icons are placed in a scrollable launcher at the bottom of the screen, which is completely customizable. ($1.02 for the premium version, Android Market)

SPB Shell 3D for Android: Expensive, but awesome, the SPB Shell app gives your phone an incredible new interface. In addition to serving as a homescreen replacement, there are new widgets, over 60 skins, folders, and more. Performance will vary on different devices. Engadget ran tests and reviewed the app here. ($14.95, Android Market)

Typo Clock Widget: Making your Android pretty? This new widget lets you add a clock and calendar widget to your homescreen. Via: AndroidGuys. (Free, off-Market APK)

SwipePad: This new launcher is revealed by swiping, no matter what application you're in at the time of the swipe. (Free, Android Market)

Ninua News Reader: From the same folks behind the Facebook app NetworkedBlogs, comes Ninua, a social news reader for Android. The app lets you follow friends, share reading lists and more. Louis Gray has the review. (Free, Android Market)

LinkedIn: At last, business networking site LinkedIn came to Android this past month, giving users the ability to search, message, view updates and more. Our coverage. (Free, Android Market)

Contapps: This app re-imagines the deafault Contacts app with a new look and feel, plus social connections to Facebook, Twitter and more. (Free, Android Market)

RadioMe: An Android app radio that "plays" your social media from Twitter, Facebook, Gmail and more, using text-to-speech synthesis. (Free, Off market APK)

FlexT9: A powerful keyboard replacement app that's much like SwiftKey and Swype combined as it supports speaking, tracing, writing and tapping, while offering word predictions at the top. ($4.99, Android Market)

Succotash: This location-predicting application uses your Google Latitude history to predict your current location, which can then be shared with friends. You sign into Succotash with your same Google Latitude account in order to use. Great for when your location goes stale. (Free, Android Market)

AutoCAD WS: This free app is a mobile CAD application that lets you use simple viewing, editing and markup tools to work on your designs while on the go. Sync files from the Web or upload directly from AutoCAD itself. (Free, Android Market)

PSX4Droid: Despite getting booted from the Android Market, this PlayStation emulator app popped up online soon after delisting. (Free, Off-Market)

Webroot Mobile Security: A new way to safe safe on Android, Webroot's premium app blocks and removes malicious apps, protects your contacts and passwords, blocks phishing attempts, locates missing devices, stops unwanted calls and text spam, runs scans, analyzes the permissions given to apps and more. ($14.99, Android Market)

Bonus Section! iPad Apps

Optimum for iPad: Cablevision subscribers can get on-demand TV listings, set DVR recordings and watch videos on demand with this new app, which also includes around 300 live TV channels. (Free, iTunes)

Zoho Docs for iPad: The Google Apps competitor delivers mobile access to files created in Zoho Writer, Sheet, Show and Docs. You can also view shared files with the app. Our coverage. (Free, iTunes)

StackPad: This iPad app lets you make photo collages with images from your photo gallery. Just drag, drop and resize. TNW has the review. ($1.99, iTunes)

Bloomberg Businessweek+: This new Bloomberg iPad app is a subscription-based publication featuring the same content as the print edition, plus additional, interactive content designed for the iPad. (Free app, $2.99+ for a subscription, iTunes)

Showyou: An iPad (and iPhone) app for viewing the videos your friends are sharing on social networks like Facebook and Twitter. Our coverage. (Free, Tunes).

Blogsy: This blogging tool for iPad takes advantage of touch with drag-and-drop photo and video insertions from Flickr, Picase, Google, YouTube or elsewhere on the Web. ($2.99, iTunes)

Photosmith: This app for professional photographers lets you organize your photos on the iPad before importing them to Adobe Lightroom. It's meant to be used with Apple's Camera Connection Kit, which supports most digitals and many DSLRs. ($17.99, iTunes)

Push.me HD: This iPad app lets you exchange messages and photos for free with other iPhone and iPad users or anyone using the company's online portal. ($2.99, iTunes)

Realtor.com Real Estate Search: This new iPad (and iPhone) app lets you search for houses, view property details, prices and photos, save notes and ratings, share listings with friends or your agent and more. Our coverage. (Free, iTunes)

Timbuktu: The first iPad mag for kids offers interactive features to display news and photos, all with an educational bent. The first issue offered articles on popsicles, beaches, toys and animals. (Free, iTunes

Bing for iPad: Microsoft's search engine becomes its own iPad app, complete with access to news, movies, local listings and, of course, the Bing homepage image. Our coverage. (Free, iTunes)

Bonus Section! Honeycomb Apps

Kid Mode for Honeycomb: The popular kid-distracting mobile app Kid Mode comes to Android tablets with educational games, books and the drawing app. (Free, Android Market)

FlightBoard: Now optimized for tablets, Mobiata's FlightBoard app for Android lets you check the arrivals and departures for any airport worldwide. It also includes two live wallpapers. ($3.99, Android Market)

Beautiful Widgets 3.5: One of the most popular widget makers for Android added Honeycomb support in the new version released this month. A 4x3 "Super Clock" for tablets is just one of the many new features added. ($2.95, Android Market)