There are times when I wish I could edit MP3s to sound like I want them to. I have JazzWare, and I use that to speed up or slow down MIDIs. Is there a completely free, legal way to convert MP3s to MIDIs?
its not possible to convert MP3s to midi.
MP3s are waveforms. Midis are a series of notes which are rendered by the midi driver.
There are programs that can recognise tones in audio files (like mp3) but it still works fairly crappy. A quick google search will point you to a dozen of these programs (with a free trail at least); you might be lucky with them but I don't really expect it.
I once tried to do what you're doing now with what I thought was a fairly simple piano piece. I did manage to convert it to midi, but the converting software recognised the slight reverb as separate notes in some places, leading to a whole bunch of extraneous notes. I had to manually edit all of them out. If you're thinking of anything even more complicated than a piano piece, I'd say be prepared for a whole lot of frustration.
That said, here's a freeware program to convert wav to midi: http://www.hitsquad.com/smm/programs/AmazingMIDI/
1. You can speed up audio files as well as change their pitch, with rather accurate results. If all you want is to speed up an audio file, just download audacity, or reaper and take it from there.
2. There is actually one program that translates waveforms into individual notes, etc (polyphonic). So you could potentially put in a song and get out all the notes. Check in google for melodyne DNA (both words). It's fairly difficult to use it though and it's considered one of the pro programms out there!