Your best bet would be to do a search here on the internet. There are well over 10,000 websites that debunk the conspiracy theories. Here are a few:
www.popularmechanics.com Search for the story entitled "9/11: Debunking the Conspiracy Myths."
www.youtube.com Search for the series of films "Screw Loose Change." (They can also be found on Google)
http://www.thebestpageintheuniverse.net/...
http://www.debunking911.com/
http://underground.soulawakenings.com/ti...
http://www.snopes.com/rumors/pentagon.ht...
http://www.abovetopsecret.com/pages/911_...
http://austinbay.net/blog/?p=1348..........
http://www.daylightatheism.org/2006/05/l...
Good luck!
Here are some more:
http://bloggasm.com/more-scientists-debunk-911-conspiracy-theories
http://www.geocities.com/factsnotfantasy/ExplosivesDebunked.html
http://www.collisiondetection.net/mt/archives/2006/09/_youve_no_doubt.html
http://www.iowastatedaily.com/media/storage/paper818/news/2006/07/13/Opinion/Loy-Sept.11.Fact.Not.Fiction-2131230.shtml?norewrite200610221519&sourcedomain=www.iowastatedaily.com
http://www.e-thepeople.org/article/57157/view?viewtype=best
http://drsanity.blogspot.com/2005/02/911-and-paranoia.html