So here for instance is an inexpensive model available on Amazon. Not that I want this phone particularly but the description raises some questions:
# This unlocked cell phone is compatible with GSM carriers like AT&T and T-Mobile. Not all carrier features may be supported. It will not work with CDMA carriers like Verizon Wireless, Alltel and Sprint.
# Unlocked Quad-Band GSM cell phone compatible with 850/900/1800/1900 MHz frequencies (Both SIMs) plus GPRS/WAP data capabilities.
I have a SIM card for Brazil/South America and Kolbi(Latin America). I don't know if those are GSM or CDMA networks. But the above description suggests it matters whether or not I have a GSM or CDMA phone. So I am a little confused there. From the links below I'm starting to see I probably need a quad band, GSM phone.