Nat and I gave a talk at the most recent London Geek Night. It was an introduction to our approach to Test-Driven Development, incidentally making the point that some of the state- vs. interaction-based TDD wars are a bit specious; it's a matter of picking the right tool for the job. We had a good crowd and some useful questions. Afterwards, there was a Code Dojo in which Nat took part while I got stuck at the back talking to people. Thanks again to our hosts for an interesting evening.
There are couple of other relevant links. Nils Haugen has a nice talk he did on Improving Test Maintainability, which is about making sure the tests make sense. Our interest is more in the stage after that, which is about listening to what the tests are telling you about the design of your code.