Saw Fahrenheit 911 last week and it was really provocative, with scenes of parents of dead American soldiers questioning the reasons why their children were sent to fight and ultimately,die, and the heavy business investments Saudi royals have in America and of course, the corporate ties of GWBush, his father and VP Cheney which involved the Saudi royals and even the Bin Laden family.
It had a lot of dramatic scenes like the American soldiers (tankers not infantrymen) talking about what kind of music they played when rushing into battle in Iraq,footage of a public beheading in Saudi Arabia, and a raid by Amercia troops on an Iraqi home at night during christmas time. It also had its funny moments like the Bonanza theme and opening credits, but with the heads of Bush, Brit PM Blair, VP Cheney and Secretary of State, Colin Powell imposed on the bodies of the main characters,
the (ridiculous but true) footage of Bush declaring he's a 'war president' and that whenever he thinks foreign policy, he 'does it with war on his mind'.

It was a very good movie, one that was informative and very entertaining to watch, however Fahrenheit 911 cannot be considered a true documentary. It is instead, a narrow, biased (though describing true images and events) and propaganda-like attack against GW Bush rather than a documentary on how and why 911 happened and the unjustness of foreign American policy. Moore personally did not try to hide this fact though, as he speaks out against Bush and his policies every opportunity he gets,
Still I found the movie had a lot of valid points and information but not a lot of depth in probing those points, such as Moore's lack of focus on those around Bush- Cheney, Rumsfeld, Wolfowitz and their actions and beliefs (if Bush is so dumb as Moore alleges, obviously Bush couldn't have come up with all this by himself, which he didn't). Another one is Moore tells how Bush and his GOP party 'stole' the election in Florida, by using his connections to prevent possible Democratic voters from voting, creating a stalemate and so causing the elction to be decided in the Supreme Court where the majority were GOP appointees (appointed by Republican administrations). From then on,Bush and his 'regime' went on the rampage, hiding poor domestic policies from the attention of the public (disproportionate large tax cuts for the rich, refusing to sign the Kyoto protocol on environmental standards etc.) by starting foreign military 'crusades' using a combination of terrorism and vague and untrue reasons. Yet throughout all this, Moore did not mention anything about how or why most of the opposition went along with all this, especially back to the election footage, the night of the election when a number of black (Democratic) congresspeople petitioned and made impassioned pleas to VP Gore (in his dual role as president of the Senate) for a recount but could not because no Senator (GOP or Democractic) agreed to sign the petition. Moore paints it as Bush screwing the blacks of America, both in society and in Congress but essentially they were also screwed by their own party.

The greatest danger is that Moore has focused so much blame and ridicule and anger on GW Bush that people are likely to think that Bush is the main (and only) evil and that to get rid of it, to restore their nation to its past glory and righteousness, Americans need only to elect the other party's candidate to office. There are so many factors, so many issues and problems that go beyond just GW Bush and his Saudi business connections that nothing would end with his defeat.
There is a lot of criticism towards this movie, but besides the usual Bush supporters and Republican (Bush's party) right-wing backers, there's also criticism from anti-Bush and leftist individuals,writers, intellectuals and activists.
Here's a few of these articles, this one from Counterbias, points out the absence of mention of Israel and the 'neo-cons', a group of politicians, thinkers and powerful people in society whose main philosophy is that the use of american power to change foreign nations ensures American dominance and progress. Whatreallyhappened.com has a list of questions for M. Moore on his implications of the Saudis and 911. This posting on libertyforum.com has a detailed account by an individual who cares deeply about the state of his country and he points out valid concerns that the movie only focuses on GW Bush thus making him seem as the source of all evil, whilst ignoring the larger picture of what caused 911 and consequently the unjustness in the American nation and its leaders,both Democrat and Republican.

Here's a very controversial inference to be found in the movie:
Using the official and widely accepted version of the events of 911, 19 Arabic 'terrorists', members of Al-Qaeda, hijacked 4 planes and succesfully crashed 3 of them into their planned targets, causing great loss of life and the destruction of the WTC.
Osama Bin-Laden is the leader of Al-Qaeda, born into a rich family with close ties to the Saudi royal family, and with business investments in the US. From offiical reports made by the US administration and the US media,Osama was supposedly estranged from his family, the black sheep yet in Fahrenheit 911, Moore states that Osama wasn't as cut off from his family as reported as one of his brothers had attended his son's wedding in the late 90s in Afghanistan. then after the 911 attacks, Saudi nationals including members of Bin Laden's family were flown out of the country (Moore alleges while the ban on all flights was imposed).
I hope you see the possible connection (on how 911 happened and who were involved), one that is hugely controversial and frightening.