iJailBreak is an automated jailbreaker for your iPod Touch, licensed under the GNU General Public License v2 and written by 13-year-old AriX.
The only user interaction required is for you to restart the iPod Touch. A PPC version is in the works.
iJailBreak is heavily dependent on Niacin and Dre's awesome tiff hack, you can find them at http://toc2rta.com/. They really started the whole iPod Touch hacking scene.
iJailBreak also makes heavy use of iPhuc, which you can find at http://code.google.com/p/iphuc/