After removing rotten links, this is all that is left...
Cornelia Remi's Harry Potter Kiste - includes Character names and Chapter titles from Iceland to Estonia to Portugal to Asia, mistakes in the German edition, etc. Very interesting!
The Harry Potter Lexicon - lots of words and information.
Harry Potter Facts - all that time I was tearing my hair out, scrabbling from chapter to chapter trying to find where this character or that gadget appeared. This site has it all at your fingertips!
The Akashic Record - claims to be 'a Compendium of Lore, Onomatology, Miscellanea, and Pareidolia Relating to the Universe of Harry Potter With Commentary Esoteric and Exoteric'. the derivation of words is sometimes a bit far-fetched, but all-in-all a good resource.
Say-zan-sha's site (in English)
Introduction to Ly Lan, who did the Vietnamese translation. Includes biography and information on her many other works.
Taiwan/Hong Kong (Google is not very good for Taiwan -- too heavily infiltrated by commercial interests)
Harry Potter and the Chamber of Muggle A beautifully done site.