I have always wanted to tap natively into my Nvidia's shader engine without having to learn DirectX and now I can. Geek Joy!
It is important to note however, that SP1 Beta is not compatible with the Silverlight 2 Beta 1 Tools for Visual Studio. I recommend if you are doing any Silverlight 2 development at this time that you hold off on installing SP1 beta. Silverlight 2 Beta 2 will be out very soon and there will be an updated version of the Visual Studio Tools that works with SP1.
Kudos to Silverlight Surfer for putting this video together. Definitely worth checking out - if you do not understand what a GPU and Pixel Shaders can do for you as a .Net Developer then this video will give you an idea.