Godric's Hollow
Forum discussion about the books, movies, and Hogwarts RPG.
Gryffindor Tower
Message board with forums for each of the four books, plus rumors and Hogwarts.
Harry and Hermione's Secret Castle
A small forum for general talk.
Harry Potter by Solana and Agus
Message board about the books, movie and author. Provides news, pictures, role playing and fan fiction.
Harry Potter Chat
Discuss Potter facts and trivia with other fans.
Harry Potter for Grownups
Group dedicated to in-depth discussions of the Harry Potter books, mainly intended for grownups.
Harry Potter Message Board
Common rooms for each house, discussion of each of the books, quidditch, and general discussion.
Harry Potter's Mystik Merchant
Message board on the books, movie and characters as well as game cheats, codes and tips.
SmartGroup: Harry Potter by J K Rowling
Email and web-based discussion group where participants can discuss characters and plots, and take part in quizzes.
The Cauldron Corner
A messageboard dedicated to the Harry Potter series. Mostly dealing with RPs, there are also boards to discuss the series and many other topics as well.
Trelawney's Harry Potter Club Page
Book club which meets at Susquehanna County Library in Montrose, Pennsylvania.
Yahoo! Groups
http://dir.groups.yahoo.com/dir/Entertainment___Arts/Humanities/Books_and_Writing/Genres/Children&ap
Harry Potter related online clubs with fan fiction and role playing games.