audio file volume levels

[Kurt Kaufman]

I have a stack which uses a large number of audio files, and unfortunately 
they were recorded at various volume levels.  I would like to "even them 
out" so that they sound more matched with each other, volume-wise.  Does 
anyone have a suggestion as to a utility that can accomplish this? It is not 
practical in my situation merely to use the Rev QT player object to play 
them back at different levels; I need to actually modify the sound files 
themselves.

Thanks,
Kurt