Walter, the Southern Poverty Law Center that Setanta mentioned can be reached at:
http://www.splcenter.org. One of their finest programs is Teaching Tolerance which is used in schools and other educational forums. Their address is:
www.teachingtoleranc.org.
Starting early, helping children learn how destructive prejudice is will help more than anything else I can think of.
Also, if the media would report more success stories about the defeat of prejudice, it would go a long way toward showing that it really is possible. There was a town I read about in one of the Dakotas (I think) where vandals were throwing rocks into the windows of people who had Hanuka (sp) decorations up. Soon after the vandalism, many people started to put up the same decorations whether they were Jewish or not. Before long, there were so many homes with these decorations, that it was impossible to tell who was Jewish and who was just a friend.
If there were more positive stories showing how people work together to stop this ugliness, I think it would go a long way toward minimizing the hatred and showing how base and pathetic prejudice really is.