Conservativeimage.com, I agree that Powell's address was compelling, but I agree with Stultis that playing it at a counter-protest is probably not the best strategy.
Unless you have a mass sound system with a huge 10 feet or much larger screen, showing anything like that at a public rally will not catch the attention of the crowd. And you sure don't want to rent expensive equipment to try to play that video to the leftists, who are likely to damage or steal your rented equipment given half the chance.
I applaud your efforts, but think that you might want to try a simpler message, something that will fit on a sign. Then, you can have a more detailed handout emphasizing detailed points for the press or others.
You could include quotes from the Powell speech, but it is somewhat dated. Also, it gets back to the left "no WMD" litany of leftist lies.
I suggest trying something like the following, which points could also be emphasized in short letters to the editors of your local papers, starting about a week before the protest and after the protest, pointing out that:
"For over a year, the lead group in these anti-war protests, ANSWER, has included on its website the statement that "the anti-war movement here and around the world must give its unconditional support to the Iraqi anti-colonial resistance." ANSWER's leaders are not really anti-war. They just support the side fighting America. They support the people blowing up our troops in Iraq, beheading American civilians there, and intentionally killing innocent Iraqi civilians, including those on their way to vote."
Finally, somebody has got something. Nearly 2000 views on this post and no collaboration! I'll go if somebody else will. I can contact the media if we can get something going. Have you checked my bumper sticker designs at conservativeimage.com? Do you think any of those messages are good for posters? I can redesign any of them to poster format and upload them to my site quickly. You could then go to kinkos, have them download one and print it off on poster board for a professional look. That shouldn't cost much. I can make a Freeper design...