I love Google Earth. Here's a little excerp I found on it. Didn't know this actually.
Google Earth & Sky
I just discovered that Google Earth is also useful for astronomy. You go under View and click on Switch to Sky. Suddenly your screen is a planetarium. It’s not quite the equal yet of KStars, Starry Night or Carinasoft’s Voyager (the three programs I know best), but it’s not bad for a start, and with call-outs that integrate well with the Web.