I get asked about this a lot and, to date, my answers have been very vague as I simply didn't know what the deal was (no longer being heavily involved with SharePoint I hadn't tried it myself). Anyway, I was pleasantly surprised to see an announcement about the "Silverlight Blueprint for SharePoint". The overview states:
"The Silverlight Blueprint for SharePoint is source code and guidance for developers describing how to use Microsoft Silverlight and Microsoft SharePoint Products and Technologies together in business applications and Internet Web sites. SharePoint applications that use Web Parts can now be built using Silverlight user interface elements. This capability enables a fresh look at data exposed through SharePoint Products and Technologies using the modern graphics capability in Silverlight."
The content itself consists of samples with code walkthroughs, downloads and videos.