Goldwave isn't free unfortunately but it is a great sound program. I used it to crank out all my sounds. Mixing is a snap, running things through an EQ is easy, changing pitch, volume, etc... is simple. I've used other programs that were free, and I've yet to find a good one. Most of the great sound editors out there you can play with for a bit, then you have to pay for 'em. Goldwave is where I'd start if I were you, just to get the hang of things.
http://www.goldwave.com-----------------------
Flakbait [Delta6]
Delta Six's Flight SchoolPut the P-61B in Aces High"For yay did the sky darken, and split open and spew forth fire, and
through the smoke rode the Four Wurgers of the Apocalypse.
And on their canopies was tattooed the number of the Beast, and the
number was 190." Jedi, Verse Five, Capter Two, The Book of Dweeb