evasion 0.x Untether is a patch that will be released soon in Cydia, and with its help you will be able to transform a tethered jailbreak for iOS 6.x in one untethered. This patch is made especially for those who have tethered jailbreak to iOS 6.x using redsn0w, so only terminal owners iPhone 3GS, iPhone 4 or iPod Touch 4G. The patch is not as well tested as the applications evasi0n and MuscleNerd recommends users to restore to iOS 6.1 through iTunes, then jailbreak using a separate application, but you do as you wish.
Regarding the people who did the OTA Update at iOS 6, MuscleNerd claims that they will be able to jailbreak using evasi0n, but various errors will probably appear along the way, although for now exact details are not available. In any case, you can jailbreak even if you have done the OTA Update, so you don't have to worry from this point of view.
