Apple today released iSync 2.1 which works on all Macintosh computers with Mac OS X Tiger version 10.4 or later. iSync 2.1 for Mac OS X Tiger synchronizes compatible applications in Tiger including Address Book and iCal calendar and your iSync compatible mobile phone or Palm OS device.
iSync 2.1 supports compatibility for more devices such as the latest Motorola, Nokia, Panasonic and Sony Ericsson phones. For a complete list of supported devices, please check: http://www.apple.com/macosx/features/isync/devices.html
iSync 2.1 is available via Software Update or via standalone installer from Apple.com. More info and download link (3MB) here.