An excellent site. It also explains a bit about the grounds of the White House. You'll recognize the place where press conferences are held, and understand a bit of where some famous historical photographs were taken. You may be familiar with Compton's Encyclopedia on CD-Rom. This site hold many similar features, and is useful to students in various disciplines.
Most biographies also provide links to other related sites.
If you want biographical information, this is your starting point. This site is under development, and includes resources for the student studying American History up to about the year 1900. Further sources will be added as they are reviewed. This exhibit features images, a transcription, and analytical articles about the Declaration of Independence of the United States of America. Also visit the Library of Congress described in the General Links above.