Blacksnow

blacksn0w is a software unlock developed by Geohot for both iPhone 3G and iPhone 3GS users. It works with the latest baseband 05.11.07 and is scheduled to be released on November 4.

Update: Download and install blacksn0w unlock for iPhone 3G or iPhone 3GS.
you can see the movie show how to jailbreak and unlock here.
http://www.youtube.com/watch?v=S-Sbqeza78o&feature=related