I have seen a few hints on how to set up a Bluetooth-enabled mobile phone as a GPRS modem, so I thought I'd give mine a try. After a lot of trial and error in getting the connection to work with my Sony Ericsson K700i and Vodafone Australia, I found that data tech support was largely Windows-centric, and there weren't any comprehensive step-by-step instructions available among the hints.
So I compiled a tutorial myself, complete with appropriate screenshots for use with the SE and vfinternet.au. To make it a bit more generalized, there are also basic directions on how to adjust the tutorial to suit your own mobile service provider and phone type.
Mac OS X Hints
http://hints.macworld.com/article.php?story=20041119070202863