Interesting comparison of test driven development and writing unit tests after the problem has been solved in an article from Peer Siebel;

Then bloggers were arguing back and forth about what this means. I don't think it means much of anything--I think test-driven design is great. I do that a lot more than I used to do. But you can test all you want and if you don't know how to approach the problem, you're not going to get a solution.

Lately we have been pair programming over the problem and solving it in java code, webservices and the OSB. Afterwards we have been running off and putting unit tests over it.

To be truthful I have been really enjoying this pattern of work. It helps that Patrick is an entertaining fellow to work with, but we have had two eyes on the problem and have talked out design decisions and choices while we are working. Additionally for me there is a large element of training as well as I come up to speed on a new and complicated system.

The added bonus is we are getting a lot of work done by working in this manner.