do you have unlock phone now? mexico is using 1900mhz frequency and all of our phone have this frequency. you don't need a tri-band or quad band phone, all you need is unlock phone and the phone must works in u.s service provider. that's all!
service provider in mexico:
TELCEL GSM 1900
MOVISTAR GSM 1900

I am going to the state of Sonora, MX. I know I need a quad band phone with gma capability. Can I buy a used gms phone that is unlocked, take it to MX, buy a mexican sim card, intall into the phone and have it work? Thanks in advance for all help, Roy