Want to Learn How to Use LINQ? Check out LINQPad!
I was catching up with some of the people I follow on Twitter tonight (as a side note, I used to think Twitter was a waste of time but I'm actually finding it useful now days) and noticed that Scott Cate listed a link to a free tool called LINQPad. Wow...I wish I would've known about this tool a few months back when I was working on different LINQ queries for an application. It really simplifies building queries and also happens to be a great way to learn the LINQ syntax as well. It was created by Joseph Albahari for the C# 3.0 in a Nutshell book.
Here's a screenshot from the Website. You can download LINQPad at http://www.linqpad.net. I'm really impressed with it so far.
On a related note, if you're interested in seeing how LINQ, Lambdas and LINQ with Stored procedures can be used, you can download the sample ASP.NET 3.5 application I put together that will help get you started with the different options available in .NET 3.5.