Sebastian Bergmann pointed out a blog entry of Sebastian Nohn who has written blog about how to setup Continuous Integration with CruiseControl, Ant and PHPUnit.
First of all, I thought 'Why not Phing instead of Ant?', but the blog has a good explanation for it and also there is an interesting comment, that you actually can use Ant'sExecTask to call your Phing build files when you need to. So, it's all good. I can still use Phing for packaging my stuff into PEAR package format.
Reading through the blog and clicking on links of words I've never heard before (Selenium?), I've discovered (as you do) the whole new test driven universe. Not as I don't use unit testing. I do! But, that means I can do the test driven development even better 