Originally Posted by
gaelflyer
The visa waiver should apply. You should be able to reenter the US with the same waiver after a short trip to Canada and surrender your I-94W when to the airline when leaving the US. I think you can also give the departure form the Canadian immigration when leaving the US.
No, don't surrender your I-94W form until you leave the U.S. for the final time (which, in your case, would be your U.S.-U.K. flight). The I-94W is good for re-entry from Canada and Mexico within a short period (duration of hte I-94W?)