This is a college English course? I think it's a strange movie to pick. Independent of Moore's views, it's just very poorly constructed.
I think if your view is that guns are bad and that we need to get rid of all of them, you could make a documentary that would back that up. But Moore doesn't seem to know what his message is. As others have said, the bit on Canada seems to exactly and very effectively negate that whole viewpoint.
I hated this movie. I'd be happy to watch an anti-gun movie if it was good. I could at least enjoy arguing with it while being entertained. But Bowling for Columbine is just all over the map and not remotely cohesive.
On one side, I thought Moore's ambush of Heston was reprehensible. On the other side, I thought Heston's lack of rebuttal was at least equally unforgivable. Granted, he didn't have a chance to prepare and didn't know he was being attacked. Still though, he's the president of the NRA for God's sake. Moore wasn't coming at him with anything new or complicated. I think if you're in a position of high visibility for a controversial organization, you absolutely must be able to very effectively rebut at least the standard arguments against your position.
I think speaking before the movie is a pretty bad idea. Even if it weren't a persuasive piece, who wants their experience ruined by someone talking about the points of the movie beforehand? I wouldn't want my professor talking about Ophelia's suicide before we even started to read Hamlet.
Finally, Admiral Akbar is almost certainly right again. My biggest advice would be to be careful. Point out the movie's logical inconsistencies. Ask questions. What does Michael Moore's opinion on Canada's gun ownership due to his argument that guns are the problem in America? What message is Moore trying to get across in this movie? Is that message presented with a clear and direct view? How much of the argument is based on emotional appeal? Make an impact. Make people break stereotypes and really think about what you're saying. Don't make them say afterwards, "And there was this redneck guy in class who hated Michael Moore and was like, 'guns are my god-given right, blah, blah, blah'".
