hi I live part of the year in the usa and part in the uk. I have an iphone in the USA which works perfectly (on the ATT network). I am now in the uk for at least 4 months. It is obviously not economical to use my iphone in the uk on a USA network. I therefore have to buy a O2 contract plus a new iphone . If i do that will it cause chaos for me when i sync to my mac? I just want the info on my mac to be synced every time i use whatever phone i plug in? Any advice please, P.S : I dont need to have my US phone working in the Uk. So i rather hoped i wouldnt have to buy a new iphone and just put my o2 sim in the old one. Apparantly that wont work and will mess up all the numbers etc?