The dev team have released the Redsn0w 0.9.6 RC9 version to jailbreak iOS 4.3.1 untethered. Redsn0w 0.9.6 RC9 works with all the devices except the iPad 2 on iOS 4.3.1. Redsn0w 0.9.6 RC9 is available for both the Windows and Mac OS X. You could download Redsn0w 0.9.6 RC9 from the below link.

Download Redsn0w 0.9.6 RC9

We will be coming up with the guides to use Redsn0w 0.9.6 RC9 and jailbreak iOS 4.3.1 untethered, so stay tuned to Tips Needed for that!

Download Redsn0w 0.9.6 RC9 for Windows from here

Download Redsn0w 0.9.6 RC9 for Mac OS Xfrom here