CDMA phones technically can be unlocked but not in the same sense that people think about GSM and iDEN unlocking. Since CDMA phones do not use a SIM card, they are sort of “hardwired” to the provider that sells them. Therefore, they can only be unlocked by the provider with a special code that they absolutely will not give out over the phone. This contrasts how you might call Cingular and have them give you an unlock code so you can travel overseas and use your GSM phone with a foreign SIM card. GSM phones can usually be unlocked remotely, but CDMA phones require a bit of ‘reprogramming’ to unlock, and it’s not as simple as calling your provider and getting a code over the phone.
Generally, CDMA phones are NOT considered unlockable because it is usually impractical to do so. Sprint, my provider, will not under any circumstances activate a non-Sprint phone, so an unlocked CDMA phone would be useless to you if you use Sprint. Even if you get an unlocked CDMA phone and by some chance are able to have it activated with your provider, many of the features will not work correctly unless someone with quite a bit of technical knowledge reprograms the phone to your provider’s specifications.
So, you can see where this is a very confusing subject. Even if you can unlock your CDMA phone, who is going to activate it for you? I suggest you call your CDMA provider, whether it’s Sprint, Verizon, or whoever, and ask them if they will activate an unlocked Treo. Don’t be surprised if they either act like they don’t know what you’re talking about, or even laugh at you for asking. You may have to ask for a level-2 tech person before you even get an acknowledgement that CDMA unlocking is possible. Your best chance is with a prepaid service, as they generally do not care where the phone comes from as long as you are buying their minutes, but I would still suggest calling them and asking before you spend the money on a phone.