@Alan - you could ask the copyright owner for permission to use the original. They might be open to the idea.
If you are looking for free resources, here are a couple of links where you might find something of use:
http://larryferlazzo.edublogs.org/2008/1...-sound-effects/http://www.indiegamemusic.com/index.phpIf you have the funds and are looking for something original you can contact musicians like:
http://www.myspace.com/artimusbena or
http://www.3peakaudio.com/index.php
