Fictionwise has a brief biography of Ellison, a list of his best sellers, and a brief description of each book.
"Harlan Ellison." Authors and Artists for Young Adults, Volume 29. Gale Group, 1999. Reproduced in Biography Resource Center. Farmington Hills, MI: The Gale Group. 2003. Document Number: K1603000516.
Harlan Ellison Islets of Langerhans bills itself as a literary topography of the famous author. The site features a biography, bibliography, essays and oddities. One of the essays on the site is "Harlan Ellison - Stalking the Nightmare" by Michael Zuzel.
Harlan Ellison's web site includes a biography, bibliography, resources, news about the author, and an interview.
The Onion AV Club has an extensive interview with Harlan Ellison.
The Quotations Page has an Ellison quote used in this biography.
SF Site has an interview with Harlan Ellison by Jayme Lynn Blaschke, which first appeared in the June 2000 issue of the magazine Interzone.
Selected Books about Harlan Ellison
Platt, Charles, The Dream Makers: The Uncommon People Who Write Science Fiction. Berkley, 1980.
Porter, Andrew, editor, The Book of Ellison. Algol Press, 1978.