Dev Team has just released Redsn0w 0.9.6rc9 for Mac and Windows and PwnageTool 4.3 for Mac to jailbreak iOS 4.3.1 for iDevices and Apple TV 2G users.
Dev Team revealed this on their blog:
Three years past, the first version of PwnageTool was released for firmware 1.1.4. So today we’re excited to release another edition of both PwnageTool and redsn0w to bring an untethered jailbreak for Apple’s latest firmware, FW 4.3.1.
Jailbreak iOS 4.3.1 is available for iPhone 4, iPhone 3GS, iPod Touch 4G, iPod Touch 3G, iPad 1.