Here is a site that does more debunking of 9/11 conspiracy theories than I have ever seen:
http://us.geocities.com/debunking911/index.htm

P.S. I was told by an architect in NYC, on 9/11, that the WTC towers would collapse from the plane attacks - which is exactly what happened.

If you came to New York City now, you wouldn't see much left at Ground Zero - but the people that experienced it are still here.