Chronicles-network: JRR Tolkien: Tolkien bibliography and related book reviews.
Houghton Mifflin: J.R.R. Tolkien: Official American publisher site includes information on the books, a biography, and list of characters.
Tolkien Enterprises: A division of the Saul Zaentz Company which licenses the names from "Lord of the Rings" for use in merchandise.
Tolkien.co.uk: Official site from HarperCollins. Includes biography, some of his artwork, interviews, and video and audio files.