From what I hear, from people who've seen it, it's a simple propaganda piece that leads the viewer to believe things without coming out and saying it. It's designed to give the less informed a certain opinion of George Bush without the thought of the consequences that such propaganda creates. As a for instance it is being promoted by Hezbollah, and is roundly applauded by anti-American groups (including other terrorist groups) around the world.
From what I've heard from people who went it never actually lies the way his former movies have, but it deceives. A couple of for instances: He gives the date the Saudi flights (which included some of Osama Bin Laden's family members), but fails to mention that the flight bans were already being lifted when they were finally cleared, and fails to mention that several members of the bin Laden family were interviewed by the FBI before being allowed to leave. As an aside to this, I'm sure you'll remember that it was some time after this before Al-Qaida took responsibility for the attack, and that many people were leery about pointing towards Muslims as being responsible.
Another is the meeting with bin Laden family members in Texas. Neither Bush, nor his staff met with them. They were there on oil business and met, primarily, with oil executives. I say primarily because they also met with politicians, among those was the leader of the Texas Democratic Party.
People should get used to fact-checking Michael Moore's "facts." Also, (my English teachers are gonna want to kill me for using "also" as a bullet pointer, when viewing the movie try to remember that Michael Moore that he considers his American audience to be all morons (his words not mine) and that he considers the US to be pretty evil. It's not an attitude that lends one to trust the opinion of such a person.
On the plus side, at least he's more entertaining than Chomsky. Heck, TV Nation has been the only show I've ever actually written a letter to try to keep on the air.
I guess I'm a fair-weather fan, turns out when an entertainer's work and opinions become so hateful that the collateral damage becomes anti-Americanism (or becomes de-facto propaganda for America's enemies) I stop being a fan.