Apple has updated iSync to version 1.3. The update mainly offers support for more phones, and Apple says it includes stability improvements. From Software Update Control Panel:
iSync lets you manage your contacts, calendars, To Do lists, and Safari bookmarks across multiple Mac OS X computers and devices (such as an iSync-compatible mobile phone, Palm OS device, or iPod), so you always have your most current information with you. To sync a Palm OS device, you need to install the iSync Palm Conduit version 1.2 or later.
iSync 1.3 includes support for more phones from Nokia and Sony Ericsson, as well as stability improvements.
Before you install iSync 1.3, you must install iCal 1.5.1 or later. To download the latest version of iCal, visit www.apple.com/ical. Before you use iSync with an iSync-compatible Bluetooth mobile phone, you need to update your Bluetooth software to version 1.2.1 or later.
You can download the update through Software Update Control Panel. The download weighs in at 6.4 MB.