The following article provides most of the instructions on how to setup authnz_external and pwauth on Ubuntu Hardy.
http://www.pyxzl.net/store/authnz.php
News is just out of a new way to jailbreak your iPhone, and this time the tool is specifically designed to work "quickly and easily, without requiring a full restore." Quickpwn has been released as a beta, intended to complement the main PwnageTool.