I've never used any wiki engines myself. Is there any one you can recommend in particular ? I'm using CentOS 5 on the server, so I would be glad to use a solution where I don't have to jump through burning loops (e. g. install a more recent version of PHP/Python/whatever) to make it work.
I use Dokuwiki for all my technical documentation, it's easy to use and has a myriad of plugins to extend the functionality.
Untar it into a www document root, set perms, point your browser to it and configure it.
jlc