The CTP (Community Technology Preview) for Visual Studio 2010 including .Net 4.0 can be downloaded from:
January 24, 2009
Microsoft Pre-release Software Visual Studio 2010 and .NET Framework 4.0 Community Technology Preview (CTP)
November 11, 2008
As of .NET 4.0, LINQ to Entities will be the recommended data access solution for LINQ to relational scenarios, as opposed to Linq2Sql
Interesting for us as we use Linq2Sql in some cases so we will change our raodmap.