The Tech threads are usually obsolete by the time one goes back to see what had been recommended. New stuff available all the time-- new thread makes complete sense.
I believe the short version of the past discussions has been that there is no way to actually convert them-- that you have to do as George suggests. And I believe Nick's suggestion of Audacity does just that. I've used Total Recorder to do it also. I have not enjoyed the result overly much-- it never sounds as good as the midi did or as good as other wavs or mp3s, either. The result has been useful for reference or learning, but not much else.