The iPhone Dev Team, jailbreakers of all things iPhone, have released a demonstration video of a version of yellowsn0w they dub "ultrasn0w" that purportedly unlocks every version of the iPhone running everything from 3.0 on down the line.
The iPhone Dev Team has got us excited (and Apple worried) by announcing they have a fully-working software carrier unlock ready for the 3.0 firmware ahead of its official release.
The iPhone 3G unlock is now available. The unlocking software is called yellowsn0w, runs as an invisible application, and it's very easy to install. Here's how. Updated 3: Now works for me with 0.9.4.