Sorry if its already been posted, but I have been trying without success to nonroot flash my uk xoom to ICS, and last night came across
this link with the simplest method yet...
just download the rar and follow the instructions and its done and dusted in minutes...
doesnt even need that OTG usb adapter, it works right from the standard pc-xoom cable...
did mine last night and it flashes it to ged honeycomb, then run the updates and few mins later its ICS'd.....