I am an enthusiast of Test Driven Development but sometimes I have the problem that is difficult to know how to start testing. The problem usually is, very ambiguous requirements provided by the client. I know that we all have sometimes this problem and this is not an issue related to TDD, this is an issue related to pretty much any development practice.
Here is when BDD comes to the rescue.
I read this Dan North's article and everything makes sense.
I have started to play around with nBehave and so far I like it, now I will love to have a pure English editor or some kind of wizard for my clients to be able to define requirements easily.