More info and links: http://stateofjailbreak.com/tutorials/jailbreakme/
In this video I show you how to jailbreak your iPhone 3G, iPhone 3GS, iPhone 4, iPod touch 2G, iPod touch 3G and iPad using JailbreakMe. It is a very simple process that simply requires you to go to http://www.jailbreakme.com/star on your device and simply slide to jailbreak. Give it a few moments then you should have Cydia on your device and the jailbreak will be done. You will need to be on iOS 4.0 or iOS 4.0.1 for the iPod touch and iPhone and iOS 3.2.1 for the iPad. If you are on a iOS 4.1 beta then you will need to downgrade to be able to jailbreak.
If you are looking for the iPhone 4 ultrasn0w unlock you will need to wait as it won’t be up for at least a day or two.