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!  :)