Archives may contain the texts of poems, books, speeches, political cartoons, and historically significant documents such as the Declaration of Independence and the Emancipation Proclamation. The materials in these sites are usually limited to official documents and older works because of copyright laws.
The following online archives are impressive collections:
American Memory http://memory.loc.gov
Archival Research Catalog http://www.archives.gov/research/arc
Avalon Project http://www.yale.edu/lawweb/avalon/avalon.htm
Electronic Text Center http://etext.lib.virginia.edu
Eurodocs http://eudocs.lib.byu.edu
Internet History Sourcebooks http://www.fordham.edu/halsall
Online Books Page http://digital.library.upenn.edu/books