2009 brings an easy option to unlock the iPhone 3G — but results vary
True to their word, the group known as Dev-Team unveiled their software unlock for the iPhone 3G, known as yellowsn0w, on New Year’s day. This software unlock will allow you to use your iPhone with a SIM card from another carrier other than AT&T (which is the exclusive iPhone carrier in the U.S.). CrunchGear did a great step-by-step walk through with pictures, and it looks very easy to do, but there are some issues, which the Dev-Team has been updating on its blog.
First of all, you need to make sure your iPhone is updated to the latest 2.2 software with baseband 02.28.00. Baseband is another name for the iPhone modem’s firmware and you can check your number in Settings->General->About on the phone.
Secondly, if you are trying to switch to a T-Mobile SIM card in the U.S., you must turn off 3G in the settings before you begin.
: