If you want to mess around with Apache2, PHP4 and MySQL on a Mac OS X client, the way to go has, in my opinion anyway, always been the free "Complete" series of packages from ServerLogistics, and I've been using them to my great satisfaction. However, lately the versions available have fallen behind the official stable releases. Thus, I've published information on how to upgrade CompleteApache2, CompletePHP4 and CompleteMySQL to the latest releases on my WebAdmin website.
The site is still very much under construction, and is at present seriously lacking in documentation of why etc., but I'd like to share my information with the community, even in its undocumented form. The scripts are using no more than what you've already got installed on your system. This means that, at present I've had to switch off some functionality in PHP -- most notably pspell -- in order for PHP to compile. A full list of what's been switched off in PHP4/5 can be found here. I'm working on getting this functionality back into PHP4/5.
At present the pages are in Danish only, but unless you are seriously language-challenged, you ought to be able to understand the instructions -- at least if you've got some Terminal experience.
[robg adds: To navigate to the update scripts, click the Apache / PHP / MySQL buttons at the top right, and then click the 'upgrading' tab on the left side of each app's specific page.]
Mac OS X Hints
http://hints.macworld.com/article.php?story=20040923103323359