Absinthe 2.0.4 is a tool for Windows, Mac, and Linux that provides untethered jailbreaks for:

• iPad 3rd generation: 5.1.1
• iPad 2: 5.1.1
• iPad 1: 5.1.1
• iPhone 4S: 5.1.1
• iPhone 4: 5.1.1
• iPhone 3GS: 5.1.1 (new-bootrom only)
• iPod touch 3rd generation: 5.1.1
• iPod touch 4th generation: 5.1.1

Absinthe 2.0.4 runs on already-upgraded un-jailbroken devices.

Steps: Download Absinthe 2.0.4. Open it, plug your device into your computer, and follow the instructions.

Note for unlockers: if you upgrade iOS using iTunes, it will upgrade your iPhone's baseband, which negatively affects unofficial unlocks that depend on specific baseband versions.