There is nothing 'simple'
You'd really need to write wrappers for Xbox-specific functions, and probably re-write the XTL 'framework' to work with the PC. Not impossible, just a pain-in-the-ass.
I had looked into it, but by now, it's easier just to write directly for the Xbox, and with a debug BIOS, it's actually a hair more conveninent, too (remote debugging is slick).