Thankfully Samsung have not gotten into the habit of locking their bootloaders, so this should be a fairly straightforward and low risk proposition.
Firstly I'd like to thank Chainfire for doing all the hard work here. He not only developed a root method and customised CWM to work with the S3, but he also wrote a pretty easy to follow guide that you can find here at XDA Forums.
As usual everything detailed here is at your own risk, we can't be held responsible for anything you do to your device. You need to be aware that there is a real risk of bricking your device, especially if you do not follow instructions exactly.
You will possibly void the warranty on your device by increasing the flash counter, thankfully Chainfire is planning to update his TriangleAway app within the next few days to remedy this and we will likely be posting a guide on restoring your Samsung Galaxy S3 to stock. [UPDATE: Chainfire has now released an undated version of Triangle Away on the Play Store, so resetting your flash counter is now utterly simples - grab it from here].
Hit us up after the break for our detailed guide with lots of screen grabs to help you along the way (and look out for our video guide on the blogs YouTube channel tomorrow if you feel like you need even more hand-holding).
[If you don't presently own an S III, but have somehow found yourself here you might like to check out the first part of our AndroidNZ S III review here instead of clicking through to the guide]
