MuscleNerd has confirmed that the recently-released iOS 6 beta 4 can be jailbroken.
Dev Team’s MuscleNerd said that beta 4, which is the developer’s build, can be jailbreaked via the latest version of RedSn0w (0.9.13 dev 3).
As is the case with iOS 6 betas that have been released before, this version of RedSn0w is for developers only. Users looking for a jailbreak for the iPhone for general use should not utilize the latest version. It’s mainly aimed for developers who want to utilize the jailbreak in order to update their Cydia packages to support iOS 6.
If you have decided to jailbreak with the latest version, you can find the appropriate download links here.