Please disregard this post. This is not Channel 9 feedback. I will repost my question in the Coffeehouse forum.
http://channel9.msdn.com/forums/Coffeehouse/466648-Code-Testing-Using-Contracts-and-Pex/
Nice demo. Must code contracts and pex be applied in a tdd fashion? Is it possible to apply these testing techniques to 3rd party or legacy code?