An update to our "Using ADO.NET Data Services" whitepaper is now available to match the bits just released with the .NET Framework 3.5 SP1. You can find the paper on MSDN here: http://msdn.microsoft.com/en-us/library/cc907912.aspx. The document is intended to be a good way to go from 0 to 60 with data services and touches on many aspects of the product. We've got a few more docs on the way which explore specific areas of the product.
ADO.NET Data Services, Program Manager