Well, there are some conspiracies that suggest the attacks could have been prevented but were not. We needed a "Pearl Harbor" type event for our Middle East reshaping plan.
Not that what happened at Pearl Harbor was necessarily treason to get the country riled up, but there is some evidence to suggest it.
http://boards.historychannel.com/for...?forumID=30073
As for missles into the Pentagon... I think those extreme theories that have no rationale behind them are pretty dang pointless.