The World Wide Telescope public beta was launched earlier in this week, and it's amazing! Imagine being able to zip around the universe, exploring planets and distant galaxies using the amassed images from the world's greatest telescopes. It really changes your perspective! There are also guided tours, views of the planets and much more to see.
It's also a hint at the potential of "Software + Services" ... the incredibly rich UI takes full advantage of client software, yet the image data is so vast it's only practical as a hosted service. Contratulations to Curtis Wong and Jonathan Fay for creating this ground-breaking application.
Check it out at http://www.worldwidetelescope.org/; also there's a good article at http://www.nytimes.com/2008/05/13/science/13astr.html?ref=science!