iSync needs at least OS X 10.4.9 to work properly. It is included as part of Mac OS X 10.4 (Tiger), 10.5 (Leopard) and 10.6 (Snow Leopard).
iSync is compatible with the Nokia devices listed on this page. iSync needs a plugin to work with some of these devices: this is a small piece of free software that you can download and install yourself.
Using a Nokia E52 or Nokia N97?
Make sure your device software is up-to-date as iSync does not work with older versions of these devices’ software.
Use the list on this page to see if your device needs a plugin. If it does, follow these steps to download and install the plugin.