Recently my college's Amnesty Club (yes, they started a student branch supporting Amnesty International!) circulated petitions to the President to end this genocide. I was able to get 10 signatures to fill one petition and give it to the students. Even though it may not be the most effective thing (I wonder sometimes if such petitions ever really have an effect), it made me feel as though I'd done SOMETHING for the cause. It was also a good feeling to support the students - they were quite appreciative of getting that filled petition. You can download one and have people sign, too. This campaign is found at africaaction.org . Find your way to the Darfur Campaign and it's "take action now" section.
There is another step we can take as well. We can urge our Congressional Representatives and Senators to support the Darfur Accountability Act. The House version is H. R. 1424 and the Senate version is S. 495. Maybe, just maybe, our combined efforts might start to make some positive changes for these fellow humans going through such trials.