its tethered but it works http://www.idownloadblog.com/2012/09/19/how-to-jailbreak-ios-6-and-install-cydia/
Do yourself a favor and wait. Your i-device is going to be unstable and it doesn't help that you will need to hook it up back to a computer every time it crashes or restarts.
is this legit... Alleged untethered jailbreak for ios6. I found this, but i am afraid to try it:
http://iosjailbreaknow.com/