Okay, according to
THIS article which is posted on the front page, each Xbox game will have to be emulated independantly on the 360. Each game called on the nvidia chip differently.
There are still a lot of games yet to be released on the current generation Xbox. Do you think that any of these games are being made with 360's emulation in mind?
It would seem, to me, to be a wise idea for companies who are making games now to do this...especially since they now know how the emulation will work. Since they know how the emulation will work they can better design their Xbox games so that emulation will be possible and easy.