Motorola doesn't use the same bluetooth standards that Apple uses for iSync. If this support ever comes from Apple, it isn't likely to come until Tiger is released. I hope that the Motorola/Apple Cellphone/iTunes deal leads to greater support of Motorola's chosen standards by Apple for the next major release of OS X.

For now though, as you've already stated, you can use USB for iSync and bluetooth for file transfers (images, ringtones, videos, etc.)

You might also be interested in an application called BluePhoneElite that is currently in beta, it will allow you to do the SMS messaging from your Mac through the V3 that you asked about. Also, it gives you on-screen Caller ID information and allows you to setup some basic proximity scripting on your Mac for when you leave and enter the room w/ your V3 (assuming you leave bluetooth on all the time)

One other piece of software V3/Vxxx owners should have is a little thrown-together app called ThinAir that will let you take advantage of the OBEX Push protocal that Apple's Bluetooth File Exchange app doesn't let you use. ThinAir lets you install Java applications and games onto your V3 via bluetooth.

Links:
http://www.reelintelligence.com/BluePhoneElite/
http://www.diggory.net/grazing/ThinAir.zip

Peace
//Carbon