Here are some cool videos to follow up on Jim's post about these great new wheels from Rotacaster.
A Lego Mindstorms NXT Autonomous Quad Rotacaster Killough Platform Omni-Bot
Rotacaster Test 2 (visit his blog for other test videos)
LEGO Space Police Sentinel - Rotacaster - Mindstorms
The official page to find more info on these Next Generation Holonomic Robot Wheels by Rotacaster can be found here: http://www.rotacaster.com.au/robot-wheels.html