What is a primary source?
A primary source is first hand evidence. It was there at the time of an event. It is contemporary to the period being studied. Examples of primary sources are speeches, letters, songs, legislation, court decisions, journals/diaries, interviews, artifacts, autobiographies, and photographs.
American Memory Page: http://lcweb2.loc.gov/ammem
Avalon Project from Yale: http://avalon.law.yale.edu/subject_menus/20th.asp
NARA 100 Milestone Documents: http://www.ourdocuments.gov/content.php?flash=true&page=milestone
US History Primary Documents by Time Period: http://vlib.iue.it/history/USA/index.html
Gilder Lehrman Institute of American History: http://www.gilderlehrman.org
Smithsonian Institution: http://www.si.edu
A List of Primary Sources on the Web: http://www.lib.berkeley.edu/instruct/guides/primarysourcesontheweb.html
National Archives Digital Vaults *