NOTE: Those of you who rely on a carrier unlock MUST STAY AWAY from Redsn0w and stock iOS 4.3.1 firmware. Instead, use PwnageTool (on Mac) or Sn0wbreeze (on Windows). Files needed for the Jailbreak:
The guys at RedMond Pie has published a guide on how to jailbreak iPhone 4, 3GS, iPad (1st-gen), iPod touch 4G/3G and Apple TV running on iOS 4.3.1 (Untethered). Head over to this post to read the guide. Enjoy!
The folks at Redmondpie has written a guide on how to unlock iPhone 4 running on iOS 4.3.1 using Ultrasn0w. Head over to this post to read the guide. Enjoy!