I found this program called Audacity. It is a program for sound editting that has many excellent features; for example, you can change the tempo, speed, and pitch of the sound. You can copy, cut and paste sound pieces and put them anywhere else, and even change Real Media files to MP3. And the best of all, it's completly free! Don't pay a single penny!
I hope it helps, especially for modding the game.
Here's the link:
http://audacity.sourceforge.net/