IHOO  I would like to put in some serious praise for Nova Media (makes of the iSync Plugin), their expertise and amazing customer service. I tried all free plugins I could find to get an AT&T Motorola V3XX to work with iSync. After a few wasted hours I finally broke down and bought their plug-in having read review http://www.versiontracker.com/dyn/moreinfo/macosx/89518&mode=feedback . The funny thing was that I was too tired to notice their plugin actually doesn't support V3XX... duhh.

Anyhow, I contacted Nova Media and they were super helpful although they didn't have to be. They sent me a small phone inspector app which found that the phone was identifying itself as RAZRV3XXR_J which is not what iSync expects. Since they didn't have a version of 10.4.9 OSX he just modified an existing plugin to update iSync with the new identifier. Voila, everything worked. By everything I mean phone numbers as I didn't bother with calendar stuff. With such competence, not to mention willingness to help, I'd buy from this company anytime!  
(Version 7.1.2.3)