If you're C# developer you probably have heards about C# 3.0, LINQ, LINQ to SQL, LINQ to XML, LINQ to Entities and so on... Are you confused about these LINQ to XXXX stuff? Have you asked yourself how these modules are related?!
This is very good diagram posted in in June issue of MSDN Magazine by Anson Horton (PM in C# team):
Read full C# 3.0 overview.