The Source Code
The Linq or Language Integrated Query is a framework or component which adds query functionality into the .Net framework.
I have a HowTo on Linq which can be found here.
Linq & Mono
Linq in C# and mono worked flawlessly. It is built into the core mono runtime library of System.Core which is the same as .Net.
The only point I would like to raise is VB.NET and Linq appears to be somewhat lacking. I tried to rewrite the code in VB.NET and I literally could not get anything to compile. I will be investigating shortly to see if I can take it any further and will report back shortly.