Mock Objects
April 18, 2008 — NathanNice intro to using Mock Objects in .NET - provides some discussion on the two main mock frameworks in addition to an overview and a general idea of why and how to use this useful libraries.
Scott has a follow up article on mocks (Mocks - It’s a Question of When) discussing when you would choose to use mocking, which is here
Martin Fowler has an article about the art and science of mocking, called “Mocks Aren’t Stubs” that is also well worth reading.