This website lists up all names in Harry Potter and gives a translation in many European languages. Did you know for instance that Albus Dumbledore's name is Albus Perkamentus in the Dutch version? Go here and find out about all names! This website might be very helpful to you if you aren't an English native, so you can look up the words which can't be found in dictionary to understand the original Harry Potter Films and Books.
This site offers you very helpful information on how to get along on J.K.Rowling's official website.
A website specialised on Harry Potter humor.