Summary
LINQ to Entities and Entity SQL are competing technologies in the same space. LINQ to Entities is LINQ against a conceptual entity data model. Entity SQL is a SQL-like language against a conceptual data model. Both technologies have a learning curve, but both are also easier than writing database plumbing code.
Paul Kimmel is an architect for EDS and the cofounder of the Greater Lansing Area .NET Users Group (glugnet.org, Flint and East Lansing). Look for his book LINQ Unleashed: for C# and his upcoming book Teach Yourself the ADO.NET Entity Framework in 24 Hours (Sams, spring 2009). If you have a programming question, you can contact Paul at pkimmel@softconcepts.com.