After some delay, the unofficial iPhone Dev Team has released the ultrasn0w unlocking tool for iPhone 3.0 firmware. The current version is only functional with the iPhone 3G, but enables use of the device with any unofficial GSM carrier. American T-Mobile customers must however disable 3G access before using the hack.
To install ultrasn0w, users are required to first jailbreak an iPhone using either redsn0w or PwnageTool. Cydia or Icy is installed simultaneously, to which the repo “repo666.ultrasn0w.com” must be added. ultrasn0w itself can then be launched, after which a reboot should support the insertion of a third-party SIM card. It is not known when ultrasn0w may begin to support other iPhones.