http://www.worldwidetelescope.org

I’ve only just installed it, but I’m already enjoying the guided tours that you can download. Some of them even have an audio commentary (not that that went down too well in the office). I just hope that they don’t get diluted by the inevitable rubbish tours that millions of people feel they should create and inflict upon the rest of us (wishful thinking I suspect).

Check it out and have a play.