It seems as though the minute the iPad was announced, innumerable light bulbs went off as developers and entrepreneurs everywhere came to the same realization: "We could totally use this device as a digital whiteboard!" Indeed, a search for the word "whiteboard" in the App Store returns a whopping 170 iPad apps.

Although the device's 10-inch screen may not compare to a full-sized, physical whiteboard, it can be quite handy to use a virtual whiteboard with team members remotely, and the iPad's form factor suits itself quite well to exactly that.

As we mentioned, the App Store is loaded with these kinds of apps, and many of them are quite good. To help narrow things down, we've rounded up five of the best ones, focusing on apps that are either free or have a freemium pay model.

SyncSpace

Try it out (iTunes link)

SyncSpace has all the standard drawing and text editing tools of a digital whiteboard product, but with a few extras thrown in. In addition to the ability to share the whiteboard with others in real-time, you can export it as a PDF, post it to Facebook or Twitter and send it to Campfire, which is a nice touch for users of 37signals' popular team collaboration Web app.

The size of the canvas is essentially infinite, as you can pinch to zoom in and out. You can share the whiteboard with others in real time by switching on the "Sync Document" option. You can send an email containing a unique URL from which others can view your SyncSpace document, but for now that link doesn't work in the browser so only fellow iPad owners can collaborate.

ZigZag Board

Try it out (iTunes link)

Upon first launching ZigZag Board, you'll be prompted to set up an account. After that, there's a handy page-by-page tutorial on how to use its drawing tools and how multi-touch gestures work within the app.

The magic of ZigZag Board lies in the ability to initiate meetings from the app, enabling others to join in from their desktop browser. Those participants will see the whiteboard and observe changes in real time.

LucidChart

Try it out (Web app)

LucidChart is a collaborative drawing Web app that we reviewed previously. It has a more robust feature set than many of the native "whiteboard" apps for iPad, as it's intended to create more complex flow charts and wireframes. Think of something like OmniGraffle, but with real-time collaboration features built in.

Best of all, it's an HTML5 Web app so it works on the desktop and the iPad without the need to download a native application.

Conceptboard

Try it out (Web app)

Much like LucidChart, Conceptboard is a Web-based tool and thus can be used across platforms easily. It supports several standard document formats, which can be marked up and discussed in real-time. It also enables task management, team meetings and even inclusion of customers when necessary.


Whiteboard Lite

Try it out (iTunes link)

One of the most popular whiteboard apps in the App Store is called Whiteboard Lite: Collaborative Drawing. It allows you connect with other users via WiFi or Bluetooth. At first glance, it has a busier interface than the other apps mentioned here, but the drawing tools at the bottom of the screen can easily be hidden so you can make the most of the canvas.

These are by no means the only options out there. What other whiteboard apps have you used and would recommend? Let us know in the comments.