Here's an ongoing online demonstration you can participate in, if you are so inclined:
Attack Iraq? NO! An Online Demonstration. You can even put a logo on your site to oppose the war. (I'm deep in video footage land right now but am planning on getting on of these up this weekend...

# The way to honor the victims of September 11th is through peace and healing. We must spare additional innocent families the suffering that thousands of American families already have experienced. By continuing to perpetuate the cycle of violence and retaliation, we are doing a grave disservice to the victims of September 11th and their loved ones. [more: 1, 2]

# The best way to support our troops is to bring them home now. [more]

# The only weapon that can save the world is non-violence. [source]

# According to Pentagon figures, a preemptive strike could kill some 10,000 Iraqi civilians not to mention several young American men and women. [source; current body count]