WIDI is designed to automate transcribing of music. That means that the task of retrieving music score from an audio record, which is usually accomplished by a hard work of a professional musicians,is about to be solvable by a computer. You can take you favorite audio record and convert it into notes.
WIDI allows both monophonic and polyphonic conversion. You can even record your own voice and then convert it into score! Then you can change it in any way, print, reassign instruments, cut off some notes, add new, etc. with your favorite MIDI Editor (such as CakeWalk).