I looked this up recently after reading about it in Bass Player (evidentially they use it to transcribe songs). Their website says:
"It is important to understand that Transcribe! does not attempt to do the whole job, processing an audio file and outputting musical notation or midi - this would be nice, but is a currently unsolved research problem"
If you're just looking for something to slow songs down so you can figure them out, you might want to try this program that someone posted in the free software thread.
http://www.xs4all.nl/~mp2004/bp/
