Porting console games to PC

Generally it takes a few years before PCs are powerful enough to accurately emulate consoles and sometimes the console manufacturers will really go after the emulator programmers making it very VERY hard to get your hands on one.

Until the technology catches up and well exceeds what is required to run a virtual 360 in your PC, you probably won't find one. I haven't gone looking though so maybe someone decided push the envelope a bit.

All in all, I'd recommend either waiting until they get ported to the PC by the publisher (if that happens at all) or getting a 360.

i think the most recent console to have been emulated is the gamecube... although i've heard of an original xbox emulator, i haven't seen it in action (although the GC one i saw ran at 6 FPS  )

This is where you want to be
http://www.emulator-zone.com/
Don't expect much from any of the PS2 or Xbox emulators though. All the emulators for earlier consoles and or the handhelds work really well though.

The key problem is that because these are fairly simple free time projects they are having to emulate all of the graphics, sound, and processing of the console in your processor. This means that for current gen you are way behind in processing power required to emulate.

It just is not at all simple, or even debatably feasible to create an emulator that can utilize your graphics card to any substantial degree. A large part of this is the fact that you would pretty much have to recode the most difficult 2/3s of your emulator for each major graphics chip on the market. It simply is not worth the gargatuan effort required.

Ive got up to a ps2 emulator, but it runs somw games(mortal kombat annilation) like crap, others it runs pretty well

Well as long as that x86 based console used a PC standard API anyway. If it used a proprietary API then you still have the problem of incompatability with the vast majority of graphics cards on the market.