The guys over at HackTheiPhone have come out with another one, with this hack changing the iPhone so that you can use it with your old AT&T/Cingular SIM card from a different phone. This allows you to use the voice services of the iPhone without having to start a new contract.

So, to take advantage of this hack you’ll need an iPhone, another phone with an AT&T SIM card that you can use and enough time to follow the 19 step process to make your old SIM card work with your new iPhone. Note that this process does look a little easier than the iPhone ringtone hack as there appears to be about four fewer steps involved.

via CellPhoneBeat