A couple of months ago we announced that we are developing EF in an open source code base. As part of our ongoing effort to make it easier to get involved in the next version of EF and provide feedback we are now making nightly builds of the open source code base available.
There is a Nightly Builds page on our CodePlex site that provides instruction for using nightly builds.
Be sure to check out the Feature Specifications page for information on the features that are being added to the code base.
We make no guarantees about the quality or availability of nightly builds.
Entity Framework Team