Author Marcus Chown demos The Solar System for iPad, from TouchPress and Faber.

This breakthrough electronic book takes users on a tour of the solar system, filled with fully-manipulable 3D rendered planets, moons and objects, an interactive orrery, and narrative written by author and astronomer Marcus Chown.

http://www.youtube.com/watchwatch?v=DDwnHP-tUz0&feature=youtube_gdata

Footnote:
Marcus tells me that 25,000 copies were sold in the first month after publication so publishers Faber will be very happy.