This MultiTouch Behavior can be added very easily to an element in a Windows Phone 7 application and enables multitouch manipulations for Scale, Rotate, Translate.
V0.5 is published on Codeplex under the MS-PL license.
Note: Use V0.5.0 with the April CTP, and V0.5.1 with the July 2010 beta.
Stay tuned to my Twitter feed (@LBugnion) and my blog (http://blog.galasoft.ch) for new developments.
A detailed tutorial is available here.