Jailbreaking is a process that allows iPhone and iPod Touch users to run unofficial code on their devices bypassing Apple's official distribution mechanism, the
App Store. Once jailbroken, iPhone users are able to download many applications previously unavailable through the App Store via unofficial installers such as
Cydia and
Icy. These applications can make changes outside of the application which official app store applications cannot. Bellow is a link to an application that Jailbreaks each of the iPod touch's and iPhones firmwares.
RedSnow