I have just had an article on TDD for asp.net accepted by aspnet pro magazine (www.aspnetpro.com) - should be the cover article in the November or December issue.
TDD is gaining in popularity as project managers and developers start to realize the benefits of producing verifiable, reliable and robust code using this methodology and related techniques. This article will show you how to start using TDD for asp.net projects and how those benefits can be realized.
I am currently writing a follow up article that will go into more detail on refactoring, mock objects and testing the UI.
If you are interested in TDD and would like to get up to speed on using it in .net see the bbits course here: http://www.bbits.co.uk/Services/training/default.aspx?tdd and the community site here: http://www.testdriven.com/