Untethered jailbreak is available for iOS 5.0.1 firmware on iPhone3GS, iPhone4, iPhone4-CDMA, iPad1, iPod touch 3G, iPod touch 4G.
1. If you’re already on iOS 5.0.1 with a tethered jailbreak, you have two even choices:
Run redsn0w 0.9.10 over your current jailbreak (deselect “Install Cydia”)
Install the Cydia package prepared by the chronic devteam. It is called Corona 5.0.1 Untether. (tutorial)
2. If you are not on 5.0.1 yet, update now! If you unlock via ultrasn0w or gevey, make sure you update to 5.0.1 via a custom IPSW! See our guides for sn0wbreeze here. Once you’re at 5.0.1, use the latest redsn0w 0.9.10 to both jailbreak and untether.