iOS 5

Supported Devices for iOS 5

iPhone 3GS, iPhone 4, iPhone 4S, iPod Touch (3rd and 4th generation), iPad (original), iPad 2 and iPad (3rd generation)

Visit Greenpois0n to jailbreak iOS 5 devices with Absinthe 2.0.4

greenpois0n-ios5-jailbreak

Below is a video showing you how to use Absinthe 2.0.4 to jailbreak iOS5

Another option is to use the Redsn0w method to jailbreak iOS5 or iOS6. See here