After finally playing around with Leopard Server, I realized there’s not much to their calendar server GUI. It relies mostly on Workgroup Manager settings, and for Open Directory to be turned on. Once I had a basic understanding of how it worked, I was able to search more effectively for a way to implement it on Tiger Server. I found this link, which worked well for me. After following the instructions, I was able to add my account in iCal and sync across two leopard clients. I wasn’t able to get the group thing figured out, and the web interface is a mystery to me (as in, why do I need it?). I’d have to get more comfortable with managing it if I were going to set it up on a larger scale, but at least it’s working! :)