Do any of you know of any education companies who are using the iPad for education or studying purposes? Or perhaps working on making the iPad a study-aid?

My parents got me an iPad for Christmas so I could study for the GMAT. I know that Princeton Review and Kaplan have some books and study aids that work, but I'm looking for more. (BTW, Kaplan is giving away free books for iPad at FreeKaplaneBooks.com, if you are interested)

I'd love to hear your thoughts, and hopefully get some tips for my studies!

Cheers,

Drew H.