Jim Johnson has a new post about how to use TxF with the new model in Vista RC1. You will obviously need the RC1 bits to mess around with it.
I'm hoping to expand on this topic in the future to show some code samples of using it not only by itself, but also using it with SQL and the like. I'll also have some "context" posts around that describing the architecture and relationships around TxF so you can better understand the articles.
Until then, go check out Jim's post :).