Apple has got a great set of Guided Tour videos up for 14 of their built-in and available (paid via the App Store) apps for the iPad 2. They include some of the basic apps like Mail and Safari, as well as new additions launching at the same time as the iPad 2 like FaceTime and iMovie.
They’re all pretty short and sweet, and provide a great overview of some of Apple’s top iPad apps. Amongst those missing, and hopefully to be added soon are Photo Booth and the iPad iWork suite (Pages, Numbers, and Keynote).
Here’s the Apple page for these guided tour videos: