Wikipedia
- Article describing plot, cast, and merchandise.
- http://en.wikipedia.org/wiki/Underdog_(film)

Rotten Tomatoes: Underdog
- Review links, synopsis, critical consensus, credits, photos, trailers, news, box office numbers, and a forum.
- http://www.rottentomatoes.com/m/underdog/

MovieWeb: Underdog (2007)
- Facts and figures, synopsis, videos, photos, and news.
- http://www.movieweb.com/movies/film/41/3941/summary.php

IMDb: Underdog (2007)
- Photo gallery, plot outline, cast list, trivia, quotes, user reviews, and a message board.
- http://www.imdb.com/title/tt0467110/

IGN Movies: Underdog
- Provides information, news, videos, and a photo gallery.
- http://movies.ign.com/objects/483/483091.html

New York Daily News
- Review, by Jack Mathews. [Rating: 2.5 out of 4]
- http://www.nydailynews.com/entertainment/movies/2007/08/04/2007-08-04_have_no_fear_caped_k9_movie_isnt_a_dog.html

Premiere: Underdog
- Review, by Glenn Kenny. [Rating: 1.5 out of 4]
- http://www.premiere.com/moviereviews/3997/underdog.html

Yahoo! Movies: Underdog (2007)
- Details, trailers, cast and credits, reviews, photos, links, and a message board.
- http://movies.yahoo.com/movie/1809426137/info