Yep, it was bound to happen. One of the people chosen for the preview has leaked the actual update online. All you need is the code and a USB thingy and it is all yours. The catch?? If you are not one of those that should have it you will lose access to LIVE until 19th November!!
Not really worth the risk with Call of Duty 5 and Gears of War 2 just round the corner now is it??