Googling for "MP3 to MIDI" returns plenty of links. Searching
groups.google.com returns almost as many contributions sceptical of the
programs' efficacy, except with the simplest of tunes.
The greatest musical geniuses would have problems transcribing music
just by listening to it. According to legend, W.A. Mozart did it at
least once (Alegri's "Miserere"), an a-capella work for 9 voices.