I have had a few people saying that LINQ to SQL is hard to use for Separation of Concerns, so I've created a small project that show how to do it.  I have used the MEF as my SoC framework.

Project is using .Net 3.5

SoCLINQ2SQL.zip (905.61 kb)

To enhance this it is worth look at Mike Hadlow post of Repository.GetById using LINQ Expression Syntax