Fanfiction.net - Extensive Harry Potter section; each story is individually rated to be viewed at the reader's discretion. - http://www.fanfiction.net/l/224/3/0/1/1/0/0/0/0/0/1/
Phoenix Feathers RPG - Harry Potter roleplay. Fan fiction writing with an emphasis on staying in genre. Database to manage all characters. - http://phoenixfeathers.net
Ivory Gate of Dreams - Tales from the world of Harry Potter. Membership required. - http://groups.yahoo.com/group/Ivory_Gate_of_Dreams/
Ginny Potter - Concentrates on stories about the Harry/Ginny relationship. - http://www.ginnypotter.com
PhoenixSong.net - A varied source of fanfiction, updated daily. - http://www.phoenixsong.net
Whippy's Harry Potter Fan Fiction - Novel in progress Blood of Mud, Wing of Bat, as well as shorter related works and challenge entries. - http://www.blast-ended.org/
Timeturner.net - Features the Marauders and other characters from that era. - http://timeturner.net
The Sugar Quill - Includes editing guidelines, suggestion board, links to other Harry Potter sites, and a fan fiction archive, as well as a large writing community who are happy to suggest improvement. - http://www.sugarquill.net/
The Ink and Quill - Archive open to most forms of Harry Potter Fanfiction with older and newer release stories. - http://www.theinkandquill.com
Quidditch Illustrated - Wizarding newspaper, focusing on sporting events. Provides in depth coverage of quidditch games. [Flash] - http://www.freaksonparade.com/qi/
Perfect Imagination - Beta reader directory for Harry Potter fanfiction. - http://www.perfectimagination.co.uk