I currently own a Verizon HTC Incredible 2 cell phone.
I’m happy with Verizon (they’re the only ones that have good signal inside my house). But when I go outside the USA (I go to Guatemala often), I want to be able to switch the SIM card to one that works with a local mobile service providers. Otherwise I would have to use roaming with Verizon and that is ridiculously expensive.
I gave Verizon a call and they quickly gave me the “unlock” code for me to enter in my phone. After entering the code, the phone was immediately unlocked! They only made me agree to a very obvious agreement that if I stick another SIM card in there I acknowledged that I was no longer using the Verizon service and Verizon could would not support me while I had that third party SIM card in my phone. But if I then switched back to my Verizon SIM card and ran my phone in CDMA (or Global) mode, I would be supported again.
And one more thing, Verizon uses CDMA. SIM cards are used for GSM. So I tried removing my Verizon SIM card from my phone and I was still able to get Verizon service. Nice to know.
I then stuck a SIM card from a friend that uses T-mobile and switched my Incredible’s mode to GSM, I could make and receive calls as him. Very cool.
Pedro Liska 
What service did you use the Verizon phone with in Guatemala? Movistar? Tigo?
I still haven’t used my unlocked phone outside the US.
I’m not sure which ones provide GSM service but I wouldn’t be surprised if they all did. CDMA is only popular in the US.
I plan on asking friends and family what is the cheapest pre-paid plan and try to get that one.