The rally portion of the demonstration against the war in Washington, D.C. on Sept. 15, organized by the A.N.S.W.E.R. Coalition, was broadcast on C-SPAN2, but isn't archived there. I missed the original broadcast on Sunday, and only caught (and recorded) the rebroadcast on Tuesday, which I believe (not sure) may have been somewhat shorter (fewer speeches). I've broken up the video into a series of speeches which you'll find here, including Brian Becker, Tina Richards, Cindy Sheehan, Ralph Nader, Ramsey Clark, and members of IVAW and VFP. All are good, although if you only have time for one, start with the last one - Adam Kokesh of Iraq Veterans Against the War (the order is the order in which the speeches were given).
[Note that I tried to post these all directly here, but I kept getting posting problems. I think it might be due to excessive links or something, not sure, but that's why the link above goes to my blog rather than having the videos here]
Actually since I started this project, the video is now archived at the C-SPAN site here if you prefer that format rather than YouTube. Also on that same page is an excellent debate between Mara Verheyden-Hilliard of the Partnership for Civil Justice and the A.N.S.W.E.R. Coalition and Kristinn Taylor of the Blathering of Morons Gathering of Eagles.