Yes, Google may have Google Sky to look at the heavens, but the latest astronomy software from Microsoft Research, Worldwide Telescope, blew my mind.
In a nice and easy interface you can navigate between the heavenly bodies, look at collections of images (such as Hubble or Chandra images), and take guided tours between the stars (I especially liked the Mars Rover tour).
MS is positioning this software as an education platform. You (or conceivably a science teacher or professor) can construct his own tour or gallery. Those can be shared with communities.
By installing an additional software called ASCOM (Astronomy Common Object Model), you can actually control your telescope and stream images into the app and to the communities.
The navigation tools are easy to handle. Extra content is downloaded on demand (with full control over the rate of download and the cache). And the Search function will allow you to locate any named star, planet or constellation you like.
One important fact: this software is still in beta (and what isn't nowadays? ). You can assist by reporting bugs or misbehaviors from within the software. Beta or not - this is my (current) new toy.
Download it here (the site uses SilverLight).