Locating sounds involves intensity differences, delay times, awareness of the acoustics of your surrounding and much more. For a human of course. I don't know how far you want to go, but if you want to do real work on audio signals, you should turn to DSP rather than microcontrollers. A nice link to psycho- acoustical research, location among them: http://www-engr.sjsu.edu/~duda/Duda.Research.html