Here are some simple instructions to get the Nokia N93 or N93i working with iSync 2.3 in Mac OS 10.4. (Other iSync versions might work, if they have SyncML, but I haven't tested them.)
First download this .zip file for the Nokia N93, and this one for the Nokia N93i. (For the paranoid: you can simply unzip it and look at its contents in your text editor. It consists only of configuration text files and some small graphics). Now follow these instructions...
Note that this solution syncs directly using the MLsync. It won't need the small Apple application iSync Config. Another plus is that you have a little icon on the phone telling you when it is synchronizing. Not to mention that it won't lock the phone up like the iSync Config application does (this small application was necessary in some other hints concerning Nokia phones). I also included a nice icon for iSync.
Some tips for using the Nokia N93 as a Bluetooth modem:
Download these scripts and put them in the folder /Library » Modem Scripts. When you configure the device, just use the Nokia 3G CID1 or Nokia 3G CID2 script. You then just configure the Internet Connect application according to your provider. Hope it is useful for you, it works perfect here! If more assistance needed, I hope I can help.
Mac OS X Hints
http://hints.macworld.com/article.php?story=20070319121527332