No, it doesn't work with my V3xx.
I'm using the p2k driver from here:
http://www.faq4mobiles.de/forum/downloads.php?do=file&id=10Flashing with RSD Lite 3.3 worked, for example. But the UID Tool doesn't. It says "1 device(s) connected." When I click any of the "Read" buttons on the J2ME options pane, it says "Phone not supported." When I click "Extract data" on the UID/IMEI pane, the program crashes.
BTW, if you don't want to register with motorola, you can use one of the accounts on this site:
http://www.bugmenot.com/view/developer.motorola.com