Sky Map is a community/ web application that worked well might qualify as the Google Maps looking backwards, or to the sky. Database that is available is enormous and we can find everything from photos, videos in real time, articles on specific stars and constellations, etc ...
It also has classified types of constellations, as well as forums where you can find true lovers of the stars. And not least, provides an API that lets you make your own mashups on the Sky Map.
Skymap 
