At the Mix 11 conference in Las Vegas, Microsoft released more information on the software development kit (SDK) that will allow people to formally work with the kit on their PC (previous version were non-sanctioned hacks). They have published this page
which will contain all the news about the SDK as well as the first information about when the SDK will be available. I'm guessing this will be a plug in for their existing Visual Studio suite and hopefully will work with their free Visual Studio Express tools.
They also showed a very impressive demo of the software using data from the WorldWide Telescope that was pretty impressive and thanks to the folks at Ars Technica
you can see below.