Windows 8 will come with 360 game support, i.e. you can play 360 games on a Windows 8 PC.
There's only been rumours and speculation on that. I call shenanigans until MS confirm it (of which they haven't as far as I know).
I too doubt that will happen. If they make it so Win8 can play X360 games, then what's the point of having and selling X360.
Simple for money. No doubt it will require an online confirmation to make sure your Windows is legit firstly.
But people playing future Halo's and Gears of War's on a PC is a big selling point for Windows 8 if they do indeed go ahead with 360 compatibility. And like I said above developers have the information to inject that into future games.
Its an obvious money maker, why be content on getting someone to buy a 360 when you get them to buy Windows 8 at the same time :P
It will also increase sales for games also, and as said since Microsoft acts as a publisher for developers who need one, they can get some profit from that also.