I used the EastCoastSilicon NUTD > iCal sync. With version NUDC 4.5.3 and OS 10.4.11 on Powerbook 12" 1.33 ghz I could sync. However, literally no documentation from EastCoastSil. Listed categories to sync for NUD and iCal. However, I wanted NUD to overwrite iCal and ended up with duplicates on NUD as a result. Tried several options but worried I will screw up NUD which I'm a 15 yr user. Also, all banners from NUD went into iCal with an extra day on the tail end. Great price, reasonably successful, but between duplicates and banner extra day very annoying. No reply from EastCoast when submitting query. Scared to run the AddressBook sync lest I screw up both Contact and Address Book.