International SIM Card

I am looking for a phone that will work in the US and Brazil, I have my att sim card, and I have a coworker from Rio that is going to give me his active sim card for my travels...

I was thinking about another Galaxy s5. What do I need to do to Carrier Unlock an android device?

from xda-developers http://ift.tt/2aoNgzk
via IFTTT