How To Jailbreak iPhone 4 Using Redsn0w [Jailbreak Superguide]
Redsn0w by DevTeam allows you to jailbreak your iPhone 4 device, to get complete control over it (see why you should jailbreak here). Currently, redsn0w version 0.9.6b5 allows you to perform a tethered jailbreak to your device that has already been upgraded to firmware 4.2.1, which means you need to use redsn0w every time you boot the device, [...]
http://feedproxy.google.com/~r/cultofmac/bFow/~3/mxW5500ffMc/71690