Many stories floating around on IMC have been proven bogus by www.snopes.com (a website dedicated to investigating all types of rumors).
The site now has a special section dedicated to rumors about the Sept 11 attacks.
On the site they go into detail about these bogus rumors:
"Fake CNN footage of Palestinians celebrating terrorist attacks"
"4 thousand Jews absent from WTC on day of attack"
the infamous "tourist photo atop the wtc tower" right before the crash.
They also investigated a few which turned out to be true...
Click on the "Rumors of War" link.
They document evidence of all rumors they investigate.