via www.youtube.com
The entire chant is:
"Who dat? Who dat? Who dat say dey gonna beat dem Saints? Who dat!"
A little more history on the chant.
Congratulations, New Orleans Saints! Goin' to the Super Bowl! (though wow, Brett Favre is our local boy and Archie Manning is a long-time family friend. this couldn't be more exciting.)
Visit Velveteen Mind for personal, narrative content.