Now we know how Madonna got so far...
Antares Auto-Tune Evo Pitch Correcting Plug-In:
"Hailed as a 'holy grail of recording,' by Recording magazine (and adopted worldwide as the largest-selling audio plug-in of all time), Auto-Tune corrects intonation problems in vocals or solo instruments, in real time, without distortion or artifacts, while preserving all of the expressive nuance of the original performance - with audio quality so pristine that the only difference between what goes in and what comes out is the intonation."