Note that this jailbreak is for A4 (& earlier) devices on iOS 5.01 only (no iPad 2 or iPhone 4S). iOS 5.0 is promised soon.
More detail, including step-by-step instructions at:
Internet-tech, computer-tech, mobile-tech, energy-tech, eco-tech, green-tech, bio-tech, tech-tech, every day. That pretty much sums it up!