Ultrasn0w

The first iPhone 3G unlock. Will be released on 31.12.08. 

A demo (of a console-only version of the app though) can be seen at http://qik.com/video/729275.

Credit
The dev team.

Exploit
Relies on an unsigned code exploit in the 01.45.00 - 02.11.07 basebands.

The actual unlock works by a daemon patching the baseband's RAM on-the-fly, overriding the carrier lock code. It is not permanent because of the signature checks - the bootloader has to pass the sigchecks and the baseband has to pass them too, so any change to the baseband/bootloader cannot be made.

(Currently there's no any further information)