Previously available as part of Google Earth, Google has just launched a web-based version of Google Sky which allows you to explore the universe from the comfort of your own home.  More information about this product is available from TechCrunch.

In semi-related news, Google gained the most advertising dollars of any media company - new or traditional such as TV/radio/print/etc. - in the last year and by a long shot...which is why they can put so much money into projects like this that aren't immediately seen as potential profit centres.

(via Reddit)