Apple announced iOS 5 yesterday at WWDC 2011 which includes tons of new features and improvements. iOS 5 is still available in beta version which is only for developers. It was just the matter of 24 hours when dev-team successfully had a jailbreak on iOS 5.
Please note that only tethered jailbreak is possible at the moment. That means you’ll need to connect your phone to a computer via a USB cable and run the software again any time you need to reboot your device.