late follow up here, but my Nokia 6230 syncs well with 10.4.10 with no plist adjustments. I also use PhoneDirector. Each has their strong points (I wish PhoneDirector had used iCal and AddressBook for their implementation of those features -- AddressBook works a lot better with the 6230 firmware than the built-in address book in PhoneDirector, but PhoneDirector gets to far more features in the phone than iSync was intended for... easily as useful as the PC Suite Nokia won't port over to the Mac.

Now, if someone can come up with a source for firmware updates for the 6230, I'll be all set. Nokia's PC Suite doesn't support firmware updates for the 6230, and questions to them have yet to be answers. Heck, from their website, it would appear there may only be one qualified service center in the States for firmware updates -- NYC. I'm not driving there to get the firmware updated, and I'd rather not mail my cell phone somewhere...