I came across a few great resources on Entity Framework recently.
Check out the tutorial and the projects here: http://weblogs.asp.net/zeeshanhirani/archive/2008/12/18/my-christmas-present-to-the-entity-framework-community.aspx. This contains a very informative learning guide that includes many mapping examples, LINQ to Entities query examples, databases that are used in the examples, and much more.
The tutorial is based on the Entity Framework version 1 (introduced in .NET Framework 3.5 SP1).
Also, download this fantastic tool that lets you dynamically query Entity Framework models using LINQ:http://www.linqpad.net/EntityFramework.aspx (works with EF v1). The .NET Framework 4 Beta 2 version of the tool is available here: http://www.linqpad.net/beta.aspx.