General Reference:

Ask Dr. Math -- maintained by the Math Forum at Drexel University.  Provides help for math questions from elementary school through college.

CIA World Fact Book 2002  -- US government profiles of countries around the world.  You will find information on geography, government, economy, population, military and transnational issues.  

First Gov for Kids -- U.S. Government Kids' Portal.   It provides links to federal sites for children, including Ben's Guide to Government for Kids -- the educational component of the U.S. Government Printing Office, a guide to U.S. government for children grades K - 12.

Guide to Grammar and Writing -- This site is maintained by English professor Charles Darling at Capital Community College for use by his students and the general  public. 

Internet Public Library  -- maintained by the University of Michigan School of Information, the Internet Public Library is an excellent reference source.  Links include a reference center, Youth links, subject collections, and a special collections section.  Look at POTUS (Presidents of the United States) for comprehensive information on this subject.  Information found here is appropriate for use by all ages of students.