Well apache comes pre-installed (it's used for the web sharing stuff i believe). I read somewhere that PHP and MySQL also come with Jaguar, but you have to install them seperately.
However, here is a nice page with all of them in PKG format, ready to install.
http://www.serverlogistics.com/downloads-jag.php
I just got my first mac in 3 years, an iBook 800mhz that I intend to do some development on, so let me know how you make out with the installations :-)