Floo: Hogwarts

The Harry Potter Lexicon This is an absolutely amazing site and a vital resource for any fan fiction writer in the Harry Potter fandom! This site contains all of the information given to us in the books currently out, as well as any information Rowling has confirmed in interviews. The site contains lists of each and every single character, spell, potion, animal, device & item, village/place... ever mentioned. It also lists the differences between the American and British editions of the books (there are FAR more than you'd think!!) along with a ton of other information. Go see it now!

Spinner's End A huge site with, among its many features, a description of various wizarding places, selected character biographies, editorials, downloads, games and a host of special site tricks.

Room of Requirement A big site that has a ton of material including its own awards, an rpg, downloads, webmaster help, lists of information from the books and more.

Hogwarts Magic A large Harry Potter site with great information, news, and more.

HP Earth A general Harry Potter site with all types of great features, including cool contests! While you're there, check out their fan of the year :).

Hoggy Warty Hogwarts A great site with information on the books and movies, awards, a growing RPG game, fan fiction and fan art, forums, webmaster help, and much more.

Into the Pensieve A medium sized site with a lot of pictures and videos in addition to information about the books and movies.

Wizard City A large site dedicated to the Harry Potter fandom in general with lots of special features. In addition to the standard features, they also have a tribute to one of the characters that died, a pronounciation guide, lists of creatures and spells, a magic library and much more.

J. K. Rowling's Official Site A nice interactive site where you can learn information about the author and the books. She gives answers to common questions and has even hidden some extra information about the characters throughout the site.

The Official Harry Potter Website (Warner Brothers site) has all kinds of interactive material along with screensavers and wallpaper to download as well as information on the upcoming movies.