Cosmic Watch just crossed my desk, and I think it's cool. It's an astronomical clock for iPhone and iPad that features a real-time world clock, the ability to travel backwards and forwards in time to see planetary positions, find planets, and see the solar system from a geocentric point of view. That last concept, BTW, is apparently called digital orrery. Who knew? Cosmic Watch is priced at $3.99.
Check It Out: Cosmic Watch, an Astronomical Clock for iOS