ADO.NET team blog:
We are excited to announce that Microsoft ADO.NET Entity Framework 4.1 Release Candidate (EF 4.1 RC) is now available. This is a fully supported, go-live release. In approximately one month we plan to release the final Release to Web (RTW). We are not planning any changes to the API surface or behavior between RC and RTW, the release is purely to allow any new bugs found in the RC build to be evaluated and potentially fixed. .....
EF 4.1 Release Candidate Available