Jail-breaking your Apple iPod Touch allows you to enjoy hundreds of themes, games, applications and hacks which are not supported by Apple, although jailbreaking can be done pretty easily using free wizard styled application QuickPwn if not done properly it can render your device inoperable requiring a restore via iTunes.
Jailbreaking your device requires basic computer knowledge and should take roughly 15-25 minutes to complete on a decently powered PC/Mac computer.