Before I left for the U.S. last year, I made sure I brought with me my Nokia mobile phone with international roaming text simcard so that it'll be cheaper for friends and family back home to send me text messages. My phone is also unlocked so it is compatible with my T-mobile simcard, or any other sim card.
"Unlocked" applies to cell phones that can take any simcard, also known as GSM cell phones. For those travelling outside of the U.S., it is very handy to have an unlocked phone because many countries use GSM technology, and unlocked phones can be used both in the U.S. and elsewhere in the world. You do not even have to travel outside of the country to enjoy this benefit. Having an unlocked phone means your phone will accept any simcard regardless of which provider it came from.
If you do not have one yet, isn't it time to shop for unlocked cell phones ?