I have a Palm Treo 700P Smart Phone. Before it I had a Tungsten T and both work fine with my Mac. The Calendar software on the Palm works OK with iCal, but it's not the best integration and you need to use Apples iSync software to make it work. I tried "The Missing Sync" software for the Mac and for all of it's hype it did nothing better for syncing iCal and the Palm calendar up any better than iSync did. The shortcomings are in the Palm calendar App itself and not on the Mac side to be honest.
My biggest grip is that if I Create a multi-day, all day event in iCal, say from Monday through Friday of this week and mark it as all day in iCal, it doesn't translate to the Palm as an All Day event and shows up each day individually as a separate daily event. If I fix on the Palm so it is a multi-day all day event, it shows up in iCal as separate daily events. If Palm were still actually developing their Apps anymore I'd gripe to them, but they switching OSs for Palm and all of the old stuff is not being updated anymore. It's sort of annoying to be honest.