Professional LINQ
I am really getting into LINQ right now, so I am looking for good references to get the concepts in my brain. I ordered a copy of Scott Klein's Professional LINQ and found it to be extremely easy to understand. Other LINQ books I have read through tend to be very hard core and technical, where I found Scott's tome to be more practical in its approach.
The book is broken into 3 main sections, a basic understanding of LINQ and how to leverage LINQ in Visual Studio 2008. Then a section dedicated to each LINQ to XML and LINQ to SQL. In these sections he explores some very practical applications of LINQ that I think help a programmer that is new to LINQ to understand how to leverage this great new .NET feature.
In particular I think Klein should be applauded because he shows how to use XML Literals in VB.NET. Other books really want to focus on using LINQ with C#, thus alienating about half of the .NET marketplace.
Scott also explains how to use extension methods, which I think is another great new feature of .NET 3.5 that have not really been exploited yet by enough programmers.
Professional LINQ is definitely a book I recommend to get started learning LINQ.