Transcribe!
http://www.seventhstring.com/xscribe/screenshots.html
Transcribe! is great stuff. Not only can it slow the music down but you
can highlight a section of music and it will perform a frequency analysis
and tell you what notes are there. Furthermore, you can add notation
(like notes, chords, etc.) at points in the tune with a text area it provides.
I've transcribed a number of tunes (mostly blues) with this. It is the
best tool I have seen. Transcribing is still work but this makes it about
as easy as it gets.
If you get it, PM me and I'll send an example project that I did.