First via Simon (as usual): Installing PHP 5 on OS X (if you’re using Server Logistics).
There’s another article on phpmac.com (which seems to be an excellent site): Building and Installing PHP 5 and Apache 1.3.31 on Mac OS X 10.3.4 – the configure / make / make install approach.
Just posting those as PHP MAC developers seem to get largely ignored (perhaps because “it just works” for them). Not being part of the wealthy, MAC-using bourgeois, I wouldn’t know ;)
Any more MAC links (ideally from MAC users)?