According to /., the Windows 2000 and NT source code has been leaked. So, what does this mean? Well, (if true) it means that a hell of a lot more virii will probably spring up, as the virus writers can see exactly how Windows works, and more specifically where the holes are. Could be an interesting next few months in the IT world...
Note: In case anyone doesn't understand what the source code is; it is basically the 'recipe' for a computer program; if you have it you can 'make' Windows, or more importantly, find out how it works and change it. Think of it as Microsoft's equivalent of Coca-Cola's secret recipe.