Just to get the news out: The updated version of the Entity Framework Sample Provider that is compatible with .NET 3.5 SP1 Beta is now available in our Code Gallery page. From the description:

The Sample Provider wraps System.Data.SqlClient and demonstrates the new functionality an ADO.NET Provider needs to implement in order to support the ADO.NET Entity Framework

    • Provider Manifest
    • EDM Mapping for Schema Information
    • SQL Generation

Update: for more details on provider API changes since the Beta3 release, you can read Jarek's post here.