I know that this isn't what you asked for but LINQPad is a really great tool to teach yourself LINQ (and it's free :o).
When time isn't critical, I have been using it for the last week or so instead or a query window in SQL Server and my LINQ skills are getting better and better.
It's also a nice little code snippet tool. Its only downside is that the free version doesn't have IntelliSense.
