This app for the iPad, iPhone, and iPod Touch has a little bit of everything. Information about the solar system, videos, news, and even tweets from astronauts in space! It's a free app from the App Store...so give it a try.
GoSkyWatch App
There is a free version of GoSkyWatch for the iPad. Download it from the App Store, and go do a little star gazing! Simple to use...just open the app and point your iPad up at the evening sky to locate and learn all about the stars and constellations.