Today Microsoft released ADO.NET vNext CTP. This can be downloaded from microsoft site.
ADO.NET vNext CTP, August 2006
ADO.NET vNext CTP (Community Technology Preview)
Other documents related to ADO.NET vNext are
The ADO.NET Entity Framework Overview (June 2006)
The ADO.NET Entity Framework Overview
ADO.NET Technical Preview - Entity Data Model (June 2006)
The ADO.NET Entity Framework Overview
Next Generation Data Access (June 2006)
Next-Generation Data Access: Making the Conceptual Level Real