Easiest way to activate PHP and MySQL on Mac OS 10.6 (Snow Leopard)?

A straight to the point guide on how to configure the built-in Apache (where are the config and command files), etc. As it turns out, it already ships with PHP support and it was already running for some reason. Shock Never mind. The first thing I did after installing the OS was to set up a firewall (ipfw in this case), so having an Apache on the inside did really not matter much (probably took a few MBs of the memory). But now I need it anyway, so I'm not very upset that I didn't have to install it from scratch. Smile