Installing and upgrading help

It's not the most straightforward process in the world, mostly because there are a few choices to make. It deserves a google search and a bit of reading / thought. But this looks like a good place to start:

http://developer.apple.com/internet/serverside/modssl.html

Remember that unless you want your users to get the unsigned certificate message every time they sign in you'll need to pay money for a certificate - they check you out and make sure you are who you say you are.

I am running several test instances of Moodle on a Mac mini OS 10.4 server with a similar setup to yours. If it were me I'd not bother with SSL access unless absolutely neccessary. I would bother with turning off the accursed so-called "Performance Cache" which caches up static pages (and redirects to port 16080) and slows dynamic web sites down to a crawl (it also screws up VHOST changes, as I found out the hard way ...). All the Apple docs says that you can do this via the Server Admin application but unfortunatley I have screwed mine up (I manually deleted some log files and now I get the usual informative Apple error "A service has encountered an error" whenever I try to access the web section). If you discover a way to switch off the performance cache via a config file or other command line means, please do let me know.
Cheers
Mark