Newsround (a TV proramme in the UK) have printed on teletext this afternoon saying that someone was messing around on JK's website and somehow managed to find a note labelled July 1st which revealed to them that the title of the next book is Harry Potter and the Pillars of Storge. Personally I think this title seems a little unlikely, firstly because ut sounds silly and secondly because Newsround is a rubbish programme which is often inaccurate with its stories, so I wouldnt trust it too much, but I still thought it was interesting.
(I edited the word "storg" by adding an "e" - Broccoli)