How to use Chipmunk Voices on an MP4?

Last year, I used to listen to songs with the Chipmunk Voice effect on my MP4. It's not exactly called Chipmunk Voices but.. OK.


I was wondering, how can I do that again?How to use Chipmunk Voices on an MP4?
you can use audacity its the most known voice editor in the world heres the url for the download no viruses and i promise that





http://download.cnet.com/Audacity/3000-2170_4-10058117.html?tag=mncol