There's lots and lots of information on Test Driven Development (TDD) on the web. Much of it is very useful, but many people still don't get the primary point.
Test Driven Development is a design technique, not a testing technique.
Sure, you end up with a UnitTest suite that can be very useful for testing and provide a framework for adding tests. This is a wonderful benefit of TDD, but it's not what TTD is.
- The change of viewpoint required to do TDD.
- How the tests generated by TDD are "free," coming out of design time that is necessary in any case.
- Why I don't want to write software without TDD, ever again.
- How to get started with TDD. Elsewhere:
Emmanuel Gaillot's [http://emmanuelgaillot.blogspot.com/2006/03/explaining-tdd-to-your-baker.html Explanation of TDD] to his baker.