Test driving off a cliff...

First off. Hi guys. Long time no see.

Now on to the meat. I have recently been named a Project Manager for my company. Part of my new duties as we get our development teams up to speed with working in a team environment and using Visual Studio Team System is to use Test driven development as we write new applications. I have a general idea of writing tests, but does anyone with actual experience in this find it really useful to your team? How well do you stick to a Test driven development plan? Do you find yourself half way through development no longer writing tests?

To help me get my head around things I usually need practical examples. So say you were going to write a login module for your application, what tests would you write? What would you Assert?

Edit: Oops. Can someone move this to the Testing forum? Hit the wrong link

Moved