Learn about the USA description

Welcome to Learn about the USA, the application guide for presidents and states of the United States of America.
Study states, capitals, the U.S. presidents and more.
Sources of information:
Presidents: http://simile-widgets.org/exhibit3/examples/presidents/presidents.html
States: http://en.wikipedia.org/wiki/U.S._state
Flags: http://www.usflag.org