Microsoft recently published a Software + Services Blueprint for using Silverlight with Sharepoint.  The blueprint includes six samples demonstrating basic tasks like using Silverlight in a Sharepont web part, to advanced tasks like displaying a social network diagram using active directory. 

http://www.ssblueprints.net/sharepoint/ 

Each sample includes a video, code walkthrough, setup instructions, and a Visual Studio solution that can be downloaded separately or as a single package.

The full open source blueprint source code is said to be coming soon.