Subject: How would someone go about making the XBox a cross-platform system?

I know it is very possible to make any of the video game consoles cross-
platform (i.e. - being able to play a Playstation game on the Xbox) because 
there are emulators available on the web for computers. But my question is how 
would one go about doing that on the XBox...since the XBox is the only console 
system that has a built in hard drive, and is most similar to a computer, so 
the XBox would be an easier system to modify. This would probably not be 
supported by Micorosoft...I am just curious as to how it could be done.

Re: How would someone go about making the XBox a cross-platform system?