we have esx 3.5 and VC 2.5 and running more than 50 VMS
we need to add USB controller on windows vista VM which is running under esx but I had no option to add usb controller in my VM.
1) Not supported in ESX
2) Go for USB over ethernet device (http://www.usb-over-ethernet.com/) and (http://www.usb-over-network.com/)
Zen Systems Sdn Bhd