I've got a system that works, but it's pretty convoluted and involves two third party apps!
I sync the palm device (in my case a Centro) to iCal using Missing Sync for Palm OS. I sync iCal to Entourage 2008 using Pocket Mac's GoBetween. I've only been doing it for about a week, but haven't had any gliches yet. GoBetween actually keeps all of my categories intact, as opposed to Sync Services which sends everything to a single category named Entourage.
In this case, iCal is just the middleman. I never open iCal, I'm either working on my Centro or in Entourage.