Data Access example using Entity Framework

Does anyone know of or having any good examples of how to use Entity Framework version 2 in the Data Access layer and put an interface on it so the business layer uses the interface rather than knowing about EF? I have found some examples but 开发者_开发问答they are all from 2009 and I'm not sure how they relate to Entity Framework version 2.

This article specifically references Entity Framework 4, which is the latest release of EF.

I found the following link more helpful with separating the DAL and being able to apply TDD.

http://blogs.msdn.com/b/adonet/archive/2009/12/17/walkthrough-test-driven-development-with-the-entity-framework-4-0.aspx