A handful of documents relating to women's suffrage are made available by the National Archive.
The American Treasuries of the Library of Congress has posted images of the Declaration of Sentiments from Seneca Falls as well as several newspaper accounts of the convention.
Numerous documents and images have been made electronically available at this Library of Congress site.
Sponsored by Duke University, this site provides a searchable collection of documents from the women's liberation movement of the 1960s and 1970s.