Indiana University
Wright American Fiction Collection: Mark Twain
The full texts to Twain's lesser-known works can be accessed from this site such as "Celebrated Jumping Frog" and "The Innocents Abroad." Read facsimiles of the original books or plain text versions.
World Wide School
World Wide School: Etext of a Burlesque Biography
This site provides the complete etext for Mark Twain's story, A Burlesque Biography.