Yes and it is not possible to sync a Serene through iSync on a Macintosh. This is due to Samsung using some absurb proprietary protocol on their current generation of phones for syncing. This will be rectified with their next set of phones that run an OS based on Linux,but this is of no use to current Serene users.
The best bet to get contacts from your address book in OSX to the Serene is to copy them into a folder on your desktop and send them over by Bluetooth. If you do not copy them in to the folder as individual files (this is done by holding down the option key when you drag them from addres book to the folder) all the contacts will go into one vCard and not display on the phone. As for your calanders in iCal, there is no work around that I am aware of.
Nicholas