I just heard their Corsi clip. What he said is that some BYU professor found iron spheres that were create in the World Trade Center fires. And that the government explanation was incorrect that the burning of the jet fuels did not get hot enough to create them, but only could have been created by another fuel or accelerant that had to be present. This appears to be a plausible statement. That might make him a full blown 911 Truther in the rat world, but it is only a statement of fact. Corsi left open the door that some innocuous fuel was already present in the buildings that created the iron nodules or spheres.
If it looks like a duck, and quacks like a duck, it's probably a duck. I've listened to the Alex Jones interview. Corsi is a quack.
Corsi rejected 9/11 truther arguments. It was the Obama campaign that smeared him:
http://www.wnd.com/index.php?fa=PAGE.view&pageId=72787