Smithsonian Institution
National Postal Museum: Art of the Stamp
This website chronicles the stamp designs of the past. There are images from the Arts, Stamps with a Story, Athletics, American History, The American Scene, American Legends, Love, Flora and Fauna, Norman Rockwell, Science and Technology...
Library of Congress
Loc: Baseball Cards 1887 1914
This site from the Library of Congress provides an extensive online exhibition of baseball cards. Site also contains a link to learning exercises focused on baseball in American culture (Collections Connections).