How did she Make that sound file?http://www.aviary.com/artists/JBixby/creations/dr_who_mash
Click the link above first, when you've heard enough come back here.
Believe it or not that was made out of 5 different MP3 files.
I'm not going to explain how to do it Since Aviary has several different applications & tutorials available. Myna Audio Editor
This is a neat online editor for making & editing sound files. Have fun!