Set Up apache MySQL and PHP (development environment) on Mac OS X 10.5

"MAMP (Macintosh, Apache, Mysql and PHP) is probably the easiest way to get up and running.

With just a few mouse-clicks, you can
install Apache, PHP and MySQL for Mac
OS X!

MAMP installs a local server
environment in a matter of seconds on
your Mac OS X computer, be it
PowerBook or iMac. Like similar
packages from the Windows- and
Linux-world, MAMP comes free of
charge.

MAMP is installed in the typical Mac
fashion: very easily. MAMP will not
compromise any existing Apache
installation already running with your
OS X. You can install Apache, PHP and
MySQL without starting a script or
having to change any configuration
files!

Furthermore, if MAMP is no longer
needed, it is sufficient to delete the
MAMP folder and everything returns to
its original status (i.e. MAMP does
not modify any of the ""normal"" OS X).

Here is a MAMP video tutorial which goes through the setup and configuration of MAMP."

I would use XAMPP for Mac because of its Control Panel.