Going to America in a couple of weeks and just wondering if i could buy a iphone 3gs or iphone 4 and bring it to the uk. so my plan is to go to a o2 uk after and get a Sim (if i get the iphone 4 i will wait till o2 releases the iphone 4 in the UK so i can get micro sim) and then put it into American iphone and activate it will my plan work or will i have to jailbreak it, cause it would be to cumbersome to keep jail breaking after each update.