My conversion of the XNA starter kit to Silverlight, using SilverSprite, have been accepted into the Silverlight Community Gallery. This is really great and I hope it helps somebody out there. You can view it and download the source from the link above.
You can see my original post about the conversion here: http://laumania.net/post/Porting-XNA-starter-kit-Platformere2809d-to-Silverlight-(SilverSprite).aspx
– Enjoy!