there are several listed here
http://forum.ppcgeeks.com/forumdisplay.php?f=44 this is the titan (Mogul/PPC6800, XV6800) section, find one that's listed for verizon and install it, this same section will cover everything about your phone
and yes, WM 6.1 will be a new rom which will reset the phone so back up everything you want to keep