Good article seen on the Visual Studio Magazine.
It introduces some new features of the recently released new version (VS 2008 SP1).
Good list of links at the end of the article.
ADO.Net Data Services is going in the REST / Atom direction. Tenants of this approach claim it is simpler than SOAP. When we look at the tools and framework provided by Microsoft we can see that REST is actually hidden by APIs and LINQ. All the REST statements are computed and issued by the framework. There is almost no difference with what an SDO / DAS client programmer will experience.
This other article about the Entity Framework, is also of interest. Related: Microsoft docs about the Entity Framework.