A really awesome website for the die hard Harry Potter fans out there... you must check out www.mugglenet.com. Make sure to click on the links on the left side of the webpage.. great wallpapers, games and lot's more!!!
Interested in the origins of the characters, charms, and other names from the Harry Potter series, check out http://www.mugglenet.com/books/name_origins.shtml.
Another great Harry Potter Fan Site is http://www.the-leaky-cauldron.org/