I work on the Entity Framework Team at Microsoft.
One of the best learning resources I have found since I joined my team at Microsoft is this page Danny Simmons has just published. Look here for his post explaining it. If you have any further questions that are not covered or you feel are not clear enough, feel free to add your questions in comments here or even email me.
Danny already answers lots of questions everyday in the forums, and I like "learning by explaining", so give me a chance :)