Nothing will be able to emulate the ps3 for a long time. Consider this: the ps2 has about 300 megahertz processing speed, but a ps2 emulator often laggs on pc's with more than 5 gigahertz. My pc has 7 gigahertz, and the emulator barely runs smoothly.
Considering that the ps3 is basically a cheap supercomputer, imagine a pc that could emulate it. It would have to be around ten times as fast. I don't think that will be practical for at least 10 years (it may be possible, but just buying a ps3 is cheaper and easier).