These are iClarified instructions on how to jailbreak your iPhone 5, iPhone 4S, iPhone 4, or iPhone 3GS on iOS 6.0 to iOS 6.1 using Evasi0n for Windows.
How to Jailbreak Your iPhone 5, 4S, 4, 3GS Using Evasi0n (Windows) [6.1] [iClarified]