Source : http://iphone.fiveforty.netA small application entitled iASign was developed to activate an iPhone without going through Apple or AT&T, by generating a plist file which is then recognized as valid by iTunes during the registration process. Once the file is installed, one can then use an old AT&T subscription plan or a pre-paid card.
We are still far from being able to use the iPhone with another carrier, even though hackers are trying hard to overcome the protection. It is also quite funny to remember that some people, among them analysts, were not expecting the Apple/AT&T system to survive more than couple of days before being hacked.
[translation by Linathael]