This reminds me: an article I'd recommend, though it's now a bit dated, is "The Harry Potter Series and French Arthurian Romance" by Heather Arden and Kathryn Lorenz, from the Summer 2003 (vol. 13, no. 2) issue of Arthuriana.
Postscript: On another note, I find it interesting (re: Harry Potter) that Arthur slays Lucius in many versions of the Arthurian tales, including Le Morte d'Arthur itself (Book V Chapter VIII). Weasley-Malfoy rematch, anyone? We'll see.