How do I make my voice sound like a chipmunk in imovie?

I recently got a new mac and I'm pretty sure what I have is imovie HD. I can't figure out how ot change the pitch. People tell me to look for the Audio FX tab but where is that? I can't find it..How do I make my voice sound like a chipmunk in imovie?
You could download audacit or acustica, There both free.





And all you have to do is ajust the pitch setting, its very simple!!

money