Unfortunately, the only way to take a tour is by making a request through your respective U.S. Member of Congress, so obviously a no-go in your case. I did read in an online forum about a foreigner who used a U.S. relative to get tickets (needs to be for a group of 10 or more) as they don't check passports once you've got your tickets. That said, I don't think you're missing much -- I took the tour, pre-9/11, and found it to be quite dull. It's much more interesting to wander around the perimeter. More info about tours can be found at: http://www.whitehouse.gov/history/tours/