The official source of information on Managed Providers, DataSet & Entity Framework from Microsoft
Samir Bajaj, a developer on the ADO.NET Team recently put together a very cool Drawing Editor sample application based on the Entity Framework and backed by SQL Server. The application makes a very compelling demonstration of the Entity Framework offers and even more interestingly, the application is built so that it can switch between the Entity Framework and LINQ to SQL to show off both technologies and some of the differences/features of each.
For more information on the application design, I suggest you check out Samir's blog post at http://blogs.msdn.com/sbajaj/ and do download and play with the application or to see the source code, you can visit the Entity Framework and LINQ to Relational portal on MSDN CodeGallery.
Program Manager, Data Programmability