This made my jaw drop.
I cannot wait until the upcoming MIX 10 event to see what else is announced.
What version of XNA was this developed under, I have been unsucessful at getting xna 3.1 to install on vs2010.
From Jukka Wallasvaara, a Developer Evangelist colleague:
That’ll be the new GS 4.0 which supports VS2010.
Tools etc. can be found from http://developer.windowsphone.com/windows-phone-7-series/