A refresh of our "Overview of ADO.NET Data Services" white paper is now up on MSDN here: http://msdn.microsoft.com/en-us/library/cc956153.aspx . The document is meant to cover the high-level concepts for the product. A companion paper "Using ADO.NET Data Services" published a little while ago complements this overview with details on product features and how to use them.
Coming up next is a paper which goes one level deeper and shows how to host data services in different environments (ASP.NET, WCF, IIS, WCF self host, etc).
ADO.NET Data Services, Program Manager