As I mentioned before I talked at GGMUG last Thursday.  I talked about Entity Framework in general and specifically in N-Tier applications, such as Silverlight applications.  I think I got a few folks excited about using Entity Framework.  The key thing to remember when using EF in N-Tier applications is that EF keeps track of changes in the context object.  Unfortunately, this object does not survive the trips between client and the server.  As a result, my recommendation is to use EF in conjunction with a business layer framework, such as CSLA. You can download slides and sample project here.  Please feel free to post comments or questions.