New versions of the iPhone Dev Team's PwnageTool and redsn0w iOS jailbreak tools havebeen released, to handle iOS 4.3.1. Offering a jailbreak option for the iPhone 3GS and iPhone 4 (GSM version), along with the third- and fourth-gen iPod touch, first-gen iPad and second-gen Apple TV - but not the Verizon iPhone 4 or the iPad 2, yet - it's an untethered solution meaning you don't have to plug your device into a PC/Mac whenever you want to restart it.
Right now, only the PwnageTool works on the Apple TV, and those using ultrasn0w to unlock their device should steer clear altogether. If not, you could lose your unlock completely; the Dev Team is working on a new version of ultrasn0w that will play nicely with custom IPSW files.
As for the iPad 2, that requires a bootrom or iBoot-level exploit be discovered, so a jailbreak using the new tools are still works-in-progress. Nonetheless, the app as a whole is said to be far easier to use for both OS X and Windows, as long as you have one of the compatible devices.