Need advice on a poetry slam

I am thinking of participating in a poetry slam Friday night and was wondering if someone could answer the following questions:
What happens at a slam?
Are there any strategies conducive to victory? (I think there is prize money awarded and I am pretty stony right now.)

I am not a slammer, but I have been to a few, and know a few high ranking slammers. As I understand it:
A.) The judges are just people in the audience. The audience is encouraged to attempt to sway the judges. This may include booing the judges choices, or applauding. Or just reacting loudly to the slammer. Of the slams I’ve been to, the judges are selected at the beginning by the MC, who asks this is anyone’s first slam. If there are, they are made judges. Usually there are three, and the scoring goes from 1-10. The scores get added up, and top (three, two? I can’t remember) go through to the next round.
B.) If you make it through the first round, you will be expected to read again. So bring two pieces.
C.) Slam is, in my opinion, more wieghted on the performance aspect then the poetry aspect. Visual metaphores go over big. And humor. Things that definately don’t go over big: melodramatic angst ie: “I am a butterfly, you have collected me and pinned my wings…” And memorizing your piece, while not required, allows you to perform it better.
D.) If you can find it, there’s a couple great movies: Slamnation and Slam. The first is more of a documentary, the second is a movie.
E.) Slams are fun because you get an immediate reaction. They’re honest, and I’ve found that they have a more irreverant kind of pretention then traditional poetry readings. Basically, go with confidence, and don’t get upset if you get a low score. But if you are really looking to make money, take it from this working artist: don’t count on art to pay the bills. Fun, yes. If you’re lucky, some kicking around dollars. But I’d spend the time flyering the town with resumes rather then writing if I was really that hard-up.

Of course in this day and age it’s an Inc with a website for your assistance.