The ADO.NET Data Services team announced that the “Data Services Update for .NET Framework 3.5 SP1” (formerly known as “ADO Data Services v1.5”) has been released and is available for download. If your target is Windows7 or Windows 2008 R2 you can pick it up here. For all other OS versions you can get the release from here.
The list of new features is great; projections, data binding, row count, enhanced blob support, and especially the new "Data Service Provider" Interfaces look promising!