If you have been following the iOS jailbreak scene, you will be aware that Apple had recently released a beta version of its iOS 4.3 firmware that among other things brings personal mobile hotspot to GSM variants of the iPhone. Now, if you are a developer who has signed up to the iPhone Developer Standard/Enterprise programs, you may already have access to this upcoming iOS firmware in beta variant that you can install on your iPhone.
Now a new custom PwnageTool bundle that can jailbreak this beta version of iOS 4.3 is now out for those of you interested. Do note that the procedure is extremely complicated and do not proceed unless you are an advanced user (if you have access to the Developer Standard program, you probably are already one!). The creators have pointed out that you will need a Mac for the process. Also, the PwnageTool bundle for iOS 4.3 beta requires users to create their own ramdisk and will not upgrade baseband during the jailbreak process. Also, it is a semi-tethered jailbreak and you can find the downloadable here.
In any case, this is a complicated procedure and do not proceed unless you are well aware of the potential consequences.