Star Walk [iTunes link] has been updated and improved with new features that let you leave the earth and look back at our home planet in beautifully rendered views.

Star Walk uses GPS to get your location, and shows you the current sky above your head. Since we last looked at Star Walk the app has added augmented reality, so as you orient your phone to the sky (iPhone 3GS only) you see star maps that show just where you are pointing. You can zoom into any object and get a closeup view of the surface details of planets, or even close-ups of deep sky objects like star clusters, nebulae, and galaxies. You can click on a button and get more info on the object, and if that isn't enough you can connect to Wikipedia for even more.

Star Walk is one of the great demos of Apple technology. Standing out on any clear night, exploring the skies, and easily finding out what you are looking at is a real treat.

I think the earth view is nifty, but frankly, it probably isn't a feature you will use a lot. On the other hand the augmented reality features, the detailed star maps, and close-up images of objects in our solar system are very compelling features.

I still don't like that the app switches to Safari for the Wikipedia info. It would be nice to see the browser built in, but that's a small price to pay for the rest of the deep information provided.

Star Walk works on any iPhone or iPod touch with version 3.0 or later software. The augmented reality feature, as I said, only works on the iPhone 3GS.

At US$4.99 there is a lot to like in this program. Even better, we have ten free licenses to give away to our readers. Here are the rules:

• Open to legal US residents of the 50 United States and the District of Columbia who are 18 and older.
• To enter leave a comment on this post.
• The comment must be left before Monday October 5 at 11:59PM Eastern Daylight Time.
• You may enter only once.
• 10 winners will be selected in a random drawing.
• Prize: One copy Star Walk (Value: US$4.99)

Click Here for complete Official Rules.

Hare are some more screen shots of Star Walk to whet your appetite: