The new iCal and iSync updates seems to fix the syncing of iCal to my Nokia 3650.
I tried the information in this hint, but had such trouble with yearly events that I turned it back off. After updating iCal and then iSync last night, I tried it again. You can now select Calendars in iSync. So far, everything seems to be working.
Mac OS X Hints
http://hints.macworld.com/article.php?story=20031009114321384