To jailbreak all you have to do is visit www.jailbreakme.com on your iPhone or iTouch.
Once there you will see some instructions, scroll down and then tap Install AppSnapp. Safari will disappear and you will return to the main Home screen. After a minute or two your unit will restart. Wait till this is fully completes.
Once completed just run the Installer.app from your home screen to jailbreak your unit!
(Don't click this link from your iPhone or iTouch unless you are ready to install)