I created an iSync plug-in (30KB download) for the Nokia 6233, based on tips here on macosxhints (v 10.4.6) and on .mactomster. Please download and unzip the folder into your machine's top-level Library folder (don't overwrite an existing PhonePlugins folder, if you already have one).
Mac OS X Hints
http://hints.macworld.com/article.php?story=2007032103114872