http://appshopper.com/education/star-walk Has anyone tried this? It's on sale right now for $2.99 (normally $4.99) and I saw a review on youtube from another site and it looks awesome if you're into astronomy at all.
It's great. The first night I got it I spent hours in my backyard with my childhood telescope and a compass. I eventually spent a little more for a nicer telescope. I'm waiting for a sale on starwalk also, looks like it may offer a little more, but not x2.5 more. It's a lot of fun to see things in outerspace you can't see with the naked eye. And being able to point out astrology, planets, and constellations is impressive to some girls.
It's definitely worth the 3 bucks if you're an astronomy buff or you're in astronomy class. I had astronomy last semester and I really wish I would have bought it back then. The app does a lot of cool things for you, it even gives you your exact night sky and it includes all the constellations. Plus, the interface is really nice.
It's really a very pretty app, and it seems to be the most popular general astronomy app. The interface is good, and it allows you to set your location so that the screen matches what you are seeing overhead. And it's on sale!