http://www.pdastreet.com/forums/showthread.php?s=&threadid=25253

The iQue USB modification changes three Property List files used by Palm Desktop to identify what USB devices it can sync with.  This effectively means that the Garmin iQue 3600 can sync its Palm facilities with Palm Desktop for Mac OS X out of the box, it was just that they did not update Palm Desktop to know it. 

And more iQue related information
http://www.pdastreet.com/forums/forumdisplay.php?s=&forumid=108

Thanks for your support.  Be sure to contact Garmin to mention that you use a Macintosh, and hope that Garmin will consider supporting Macintosh users in the future.