It looks like we aren't the only team who is going to be trying out mecanums this year... just a couple of tips when searching for info, so far I have found results by searching for a couple of common spellings:
meccanum
mechanum and
mecanum
All produce results.
FIRST has info at
http://www.usfirst.org/uploadedFiles...heels_Hine.ppt
and the CD white papers have a great power point presentation called "strafing", I believe that runs you through the derivation of the formulas used for a variety of omni-drive systems.
Good luck, and have fun going sideways.
Jason