In this post Stephen Forte demonstrates how to use the code from his AsyncLINQManager.
I have a simple demo application that uses ADO.NET Data Services as a data service back end for a Silverlight application. My ADO.NET Data Service uses the Entity Framework to map the Northwind database tables of Customers, Orders, and Order Details. Once the Silverlight applications sets a service reference to the ADO.NET Data Service, you can use the client side LINQ libraries to build your application. My application looks like this, it has a drop down filled with customers, a grid with Order and a grid with Order Details. As you click on each one, it will filter the rest.