I came across this site and though I'd share it.
"The Library of Congress offers this comprehensive site with digital collections from the National Digital Library. The site is easily searchable--by topic, time period and place--and many collections provide time lines, picture galleries and narrative text, as well as suggestions for outside reading and links to related collections. You'll find information on popular culture ranging from the Emergence of Advertising in America to Baseball and Jackie Robinson, as well as more standard historical features. There are extensive documentary photos in many categories ranging from the Spanish-American War to San Francisco's 1906 earthquake."