First things first, head over to the developers center and grab the iOS 3 Beta 3 by signing up for an account.
Once you have done that then download one of these two files depending on your operating system:
- Redsn0w 0.9.13 Dev3 for OS X
- Redsn0w 0.9.13 Dev3 for Windows — Please take note: Must be an administrator or have administrator permissions in order to do this on your Windows PC.
After you have downloaded the Redsn0w to your computer open it up and then click on Extras. Then Select ISPW followed by the iOS 6 Beta 3 you have downloaded.
Now all you have to do is click on the Jailbreak options and follow the tutorial that it gives you there to Jailbreak your idevice.
Once it’s finished doing this now restart your idevice.
Now you must perform a tethered boot. Do this by clicking on extras again, selecting IPSW, and then selecting Boot into tether.
Please remember this is a tethered jailbreak which means every time you switch on your iPhone or iDevice you will need to boot it up to tether once again. Now you have finished Jailbreak iOS 6 beta 3.