Marc Liyanage had released a great PHP5 binary for Tiger which includes PDO_MYSQL, however since the transition from a 32-bit to 64-bit operating system, the module doesn't link properly certain shared libraries and Apache fails on load.
The Solution: MAMP
After a couple of painful nights trying to recompile and relink my PHP5 configuration under leopard, I've given up and installed MAMP. MAMP is great since it essentially works provides a full stack for PHP / MySQL development. On the flip side however, you're not leveraging the built-in libraries that come with Mac OS X. Download MAMP for yourself.
