One of the biggest reasons why people jailbreak their iPhone is to get it unlocked for use on unauthorized wireless networks. Although there are other unlocking solutions available, Ultrasn0w is the de-facto standard when it comes down to it because of one very simple reason: it’s stupid-easy to unlock an iPhone with it (unlike Gevey SIM), At least for an iPhone with a supported baseband.
Redsn0w 0.9.6b5 has just been released which can jailbreak and update iPhone 3GS & 3G baseband to 06.15.00 so that it can be unlocked using the newly released Ultrasn0w 1.2.
