iJailBreak is the first automated iPod Touch jailbreaking application designed for the Mac, written by a 13 year old! iJailBreak now works on both PowerPC and Intel Macs.
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/.