Scoble says that when he visited Microsoft a few weeks ago he was blown away by the World Wide Telescope. Actually he said it made him cry.
The WWT isn't available yet, but you can see a demo in this TED talk. My impression after viewing the TED talk is that it's like a Google Earth for the sky, seemlessly integrating pictures and information in a single platform.
I'm just hoping there's an OS X version--but if not, there's always Parallels or Fusion.