A friend in another country asked me to buy an iPhone4s for her and send it (its cheaper in Canada). My knowledge of iPhones is rather limited, so I am asking here. Will there be any problems with that? I see some people selling theirs, and sometimes they post "Locked to Bell" (or other company). Can that be changed, or will that be a problem? Are there any other problems I may encounter if I sent it to another country?