Jailbreak your iPad. Don't worry, it doesn't do anything bad to your device like some people would want you to believe. And in any case, you can always go back by doing a Restore in iTunes. Plus, it's legal.
Anyway - after the jailbreak (done with limera1n, from limera1n.com), use Cydia to install "Display Out". It costs just $2.99, and you can do what Steve Jobs does at his keynotes: display EVERYTHING that runs on your iPad via the DockConnector-to-VGA adapter onto a projector (without jailbreak, the adapter will just let you show photo slideshows, videos and Keynote presentations over VGA). Then just get your favorite whiteboard or doodle app from the App Store and work your magic. That's how I do it, and it just works.