Has Microsoft confirmed their stance on LINQ to SQL end-of-life?
The message I'v received is: looking forward we should really use Entity Framework in as much as possible; LINQ to SQL is basically in maintenance mode: it won't go away any time soon but it won't evolve significantly either. Meanwhile Entity Framework is evolving and also being integrated with other products/frameworks like RIA Services or WCF Data Services.
I don't know if it was just sales-speak, but we had a MS guy come into our shop to introduce us to Visual Studio 2010, and he indicated that MS still has teams working to grow EF and L2S separately.