A:Answer Yes it can be unlocked. If you are in the USA and going to Brazil, go to your service provider (AT&T, or Verizon etc.) and/or call Apple. After you explain that you will be using the iPhone in Brazil for an extended period, they wil unlock the phone. (the period should be for more than 60 days, or for several 2-months period in the coming year or two).
If you are not in the USA, but already in Brazil, you just go to on local market to buy a replacement SIM card. Take out the one that was in the iPhone when you bought it and insert the new SIM card; you'll then "charge" the new SIM card for a set amount of minutes, or local currency, and re-charge each time you've used the set amount you selected.