If you have an iPod Touch, then you know the benefit of finding apps that work offline. But some iPhone owners, too, need offline access from time-to-time. Maybe you spend your commute in an underground subway or perhaps your office building has shoddy cell coverage, or maybe you just want to use your iPhone on a plane...whatever the reason, offline access to apps is still a necessary evil these days.

Not to worry, though, lack of a signal doesn't mean you have to put your iPhone (or iPod) away - there are plenty of apps today that work offline. Here are some of our favorites.

Evernote

The newest version of the popular Evernote note-taking app introduced one of the most requested features: offline notes. Through a new button called "favorites," you can mark notes for offline access. If you have Evernote on your iPhone already (who doesn't?), then check the app store for updates because this one is a must-have. Evernote newbies can just download the app now.

Stanza

The Stanza ebook reader lets you port reading material from your computer to your iPhone wirelessly so you can take your books with you when you're out and about. Once loading up with books, you can read them anytime, whether or not you have an internet connection. Download Stanza here. (Another option is Readdle, or check out our previous article for even more ebook readers.)

Instapaper

The Instapaper bookmarking tool for iPhone lets you bookmark web pages for offline reading. As any iPod Touch user knows, mobile Safari's tendency to auto-refresh pages means you can't open up web pages and save them for later reading offline. You could also choose to buy the Pro version for $9.99 which uncaps that limit while also adding other features like tilt scrolling and an adjustable text size. Download here.

Encyclopedia

The Encyclopedia app from Steam Heavy Industries delivers a complete copy of Wikipedia to your iPhone/iPod Touch for offline access. By complete they mean the complete article text, but not references, image descriptions, user profiles, etc. Being warned, though, this app needs quite a bit of storage space: 2 GB. Download here.

NYTimes

The NYTimes iPhone app lets you read the news from the New York Times right on your iPhone. You can navigate through the stories quickly, select up to four favorite sections for one-touch access, choose to browse by photos which link to the stories upon touch, and, of course, read the news offline.

MiGhtyDocs

The MiGhtyDocs iPhone application takes your Google documents offline for access anywhere. You can't edit them and save your changes, but at least you can get to them. Currently, only text documents and spreadsheets are supported. No word on slideshows yet.

An RSS Reader

There are actually quite a few RSS readers available from the iTunes App store, many which sync with your Google Reader for offline access. However, this author's personal favorite is Byline, a $2.99 app which offers a 2-way sync with Google Reader. You can even star, share, add notes, and email your RSS feeds, just like in Google Reader itself. To really juice it up with tons of feeds for an extended period of offline time, go into your Settings app and configure it to archive 200 items instead of its default limit.