Man that sucks. I can understand all of the US using a different standard from the rest of the world (like with NTSC and imperial measurement) but having the US use two standards at once is clearly not in their own interest.
Canadian carriers are the same. The only difference is that all of the smaller carriers have been swallowed up and you basically have the choice of 'The GSM Carrier' (i.e. Rogers who grew their empire out of cable tv) or 'The CDMA Carrier' (i.e. Bell -- the government mandated telephone monopoly).