Duotrope's Digest is a free writers' resource listing over 2700 current Fiction and Poetry publications.

Directory of publishers and agents

Dedicated to promoting higher regard for crime writing

For freelance writers working in U.S. markets

Guide and directory for independent and university presses.

American Center -- a membership association of prominent literary writers and editors which seeks to defend freedom of expression wherever it may be threatened

Recordings of poets reading their work

Source of poems, criticism, literary news, and biographies

Society of Children's Book Writers and Illustrators

The official site

Detective/mystery

Website for the famous periodical, contains additional links

Freelance writing ezine