Wikipedia: Fan Fiction
Discusses history, types, and legal aspects, and offers links to fan fiction collections.
Fan Fiction FAQ
From Chilling Effects Clearinghouse.
Fan Works Inc.
Home of many different varieties of fan fiction, art, columns, and fan-made games.
Animated Lust (Rated PG!)
Dedicated to interesting or sexy animated characters. Features a forum, polls, contests, fan fiction, and fan art.
Bad Fanfic! No Biscuit!
Shows examples of intentionally bad fanfic, also known as BadFic, and explains what makes them bad. Includes a fanfic glossary.
Chilling Effects Clearinghouse: Fan Fiction
Explains the rights original authors have under copyright and trademark law and gives fan fiction authors information about when their works might infringe those rights and what might happen as a result.
Hosts online discussion and essays about fan fiction.