iPhone didn't seem to be supporting all countries on the caller ID list. For example, if the phone is being used locally in some of the unsupported countries, the iPhone's caller ID would not know how to deal with an incoming call stored in your address book. For example, you always store numbers with the country code attached, but if you travel to that country and use the country's local sim card. If you receive a call, it will appear minus the country code, and your iPhone won't be able to match it to the address book. A fix is to have to jailbreak the iPhone, then use OpenSSH so you can modify the caller ID plist in order to add the other unsupported countries. I personally hated to jailbreak it but had no choice as I needed to fix the caller ID issue. But with 2.2, Apple seems to have added caller ID support to more countries, maybe all, like all other phone companies do. For international users, this is great news as the caller ID will work properly regardless of which country your in. I'm just so happy I won't have to jailbreak my iPhone anymore!