Now that the iPhone Dev Team has released RedSn0w 0.9.13dev3, it’s easy to jailbreak the latest iOS 6 beta 3 release. This jailbreak will also work with previous versions of iOS 6 beta, such as iOS 6 beta 2.
Bear in mind that this is still a tethered jailbreak, and it will not install Cydia on your device. Since you must point to the current beta firmware, you need to be a developer so that you can access iOS 6 beta 3.
If you meet these requirements, then step right inside as we walk you though using RedSn0w 0.9.13dev3 to jailbreak an iPhone 4 running iOS 6 beta 3.