Johana Rothman has a great article in stickyminds titled What Project Managers Need To Know About Testing.  Her main point is to make testing an integral part of your project plan.  I would argue that if you are using an agile methodology testing is baked into the project.  XP and Scrum assume that you have to pass acceptance tests ...

I wanted to follow up on my last entry.  One thing I didn't mention in my last post is how the TDD is accomplished.  I believe you can use both Unit Testing and Automated Customer Acceptance tests as in standard projects, in project with MOSS.  For Automated Customer Acceptance Tests, you could use something like Fitnesse.  ...