Apple includes ProjectBuilder with the development tools package. Just for fun, I tried it with some PHP development I'm doing.
I really works well. PHP is close enough to C syntax that context-based coloring and structure pairing (quotes, brackets and parens) works as one would wish.
Additionally, the CVS integration makes CVS use almost easy. A nice surpise for those of us doing web development work in PHP on MacOSX.
Mac OS X Hints
http://hints.macworld.com/article.php?story=20020217094312187