Tarkington, Booth - Several texts online, including "Alice Adams," "The Gentleman from Indiana," and "The Magnificent Ambersons." Also some sound files. From Project Gutenberg. - http://www.gutenberg.org/browse/authors/t#a169
Tarkington, [Newton] Booth - A look at the author's years at Princeton. - http://etc.princeton.edu/CampusWWW/Companion/tarkington_booth.html
Booth Tarkington Papers, 1896-1979 - Finding aid for this collection of manuscripts, mainly correspondence, at the Indiana Historical Society. Includes biographical sketch. - http://www.indianahistory.org/library/manuscripts/collection_guides/m0274.html
IMDb: Booth Tarkington - Films based on his books and stories. - http://us.imdb.com/name/nm0850483/
Bartleby.com: Booth Tarkington - Brief profile and the text of "The Magnificent Ambersons". - http://www.bartleby.com/people/Tarkingt.html