As promised, the Dev Team has released their unlock software for the iPhone 3G -- so you can use it with any other carriers apart from AT&T. Yellowsn0w is the world’s first software unlock for the iPhone 3G.

The DevTeam warns:

You must upgrade to the latest 02.28 baseband (firmware 2.2) in order to use this unlock and also jailbreak with QuickPWN/PwnageTool and add Cydia/Installer.

Please take a note that this is a beta application—version 0.9.1— so install at your own risk.

Btw, Gizmodo said, it doesn't work very well!

Yeah, since it was still in beta version, I think it could be understood. However, bravo the DevTeam! Two thumbs up!