Medina Media Center Databases: Features a number of high quality, excellent databases – reliable, quality information!
History Matters: an outstanding website featuring tons of primary sources that a historian at George Mason University who is very interested in digital history put together.
Digital History: another outstanding website that contains both primary documents and supplemental information.
American Memory: Special collections put together by the Library of Congress – it can be a goldmine if it pertains to your topic
National Archives: Great for political documents in particular (speeches, proclamations, etc.)