Dissendium has posted an old video (from 1999? 2000?) of an interview of J.K. Rowling. We are trying to figure out what the source is -- it appears to be entirely new! If you have any information about this please let us know.
Highlights: Jo tells the audience that Harry will attend Hogwarts in his seventh year (we knew this already) and that Dudley had better watch out once Harry reaches his majority and can practice magic outside of Hogwarts (also not new canon).
Although Jo has told us that she feels uneasy speaking to crowds, the film clip is a delightful example of how funny and open Jo can be when she is relaxed and comfortable.
Transcript now posted.
Edit: AQ staffer Jules has researched this video and discovered that it dates to October 1999 when she was in the Boston area on tour. There is a related report here.