You can jailbreak recently seeded iOS 6.1.1 beta version untethered using the evasi0n but after jailbreaking tethered using redsn0w 6.1.1 jailbreak and then after modifying the systemversion.plist file. Below are the steps that will help you jailbreak iOS 6.1.1 on A4 devices only i.e. iPhone 4, 3gs and iPod Touch 4g. For other devices you already have evasi0n jailbreak which we believe will be equally applicable to jailbreak A5 and A6 devices even on iOS 6.1.1.
Since 6.1.1 is at beta stage at the moment, so this 6.1.1 jailbreak procedure is only helpful for developers who want to test their A4 devices on 6.1.1 beta.