According to the page:
iSync doesn't have support for the W580 or S500 yet, so here are plugins. Unzip and copy to /Applications/iSync.app/Contents/PlugIns/ApplePhoneConduit.syncdevice/Contents/PlugIns/
You can download the plug-in on their page. And after you unzip the program, you'll have to open up the Applications folder > Right click on iSync > Click 'Show Package Contents'. And then you can click on Contents > PlugIns > ApplePhoneConduit.syncdevice > Contents > Plugins and drag and drop the folder. Then just open up iSync > Devices > Add Device and make sure you turn on bluetooth on your phone. If a message pops up on your phone asking you if that your Mac wants to use your computer as a modem, just click Yes so that the Mac and Phone can talk to each other.
One other note: You'll have to make sure that your phone has bluetooth turned on (which I find to be the easiest way to sync) and make sure that your Phone's Name doesn't have in special characters in it, or iSync will not be able to do its job and you wont be able to add the phone to your devices.
Now, I can blame the fact that I forgot my friends birthday on the phone. I guess, everything has advantages and disadvantages.
Have fun organizing all your contacts!
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