Check out the first of 8 videos by Ken Cox about the development of CRUD application using Silverlight and Visual Basic.NET.
The tasks shown include: Creating the Silverlight project, adding the database, setting up the ADO.NET Entity data model, and implementing an ADO.NET data service.
The demo is a small, but realistic example of how to create a CRUD (Create, Read, Update, Delete) application against the familiar Northwind database. It uses the latest stuff from Microsoft including Windows Communication Foundation, ADO.NET Data Services (Astoria), and the Entity Framework.
The full source code is available for download from here.