A couple of blurbs about the next book:

Rowling Unveils Title For Sixth Potter Book
By: W. Andrew Powell on Jun 30, 04 @ 11:48 am

We may still be a number of months away from seeing the book, but author J.K. Rowling has released the name for the sixth book in the Harry Potter franchise, opting for Harry Potter and the Half Blood Prince, while still withholding any other information about what the book will be about. The follow-up to Harry Potter and the Order of the Phoenix has no official release date yet and Rowling is still writing the book, but estimates that the book could be ready for some time in 2005 are probably pretty close to the truth. Although the books were originally written for children, the series has matured greatly over the years, as you can tell from seeing the recent film adaptation, Harry Potter And The Prisoner Of Azkaban. According to previous interviews and articles with the writer, the Potter series will end with the seventh book.

So far a number have guesses have emerged as to how the series will end, but in an interview the BBC conducted with Daniel Radcliffe, the actor who plays Harry in the movies, the star allegedly offered up a fairly plausible theory. "I'm going to be really unpopular for saying this," Radcliffe said, "but I've always had the suspicion that Harry might die."

From Reuters:

LONDON (Reuters) - JK Rowling has silenced the rumour-mongers by confirming the new book in her series will be called "Harry Potter and the Half Blood Prince". The author of the multi-million selling books revealed the title behind a magic door on her official website, JKRowling.com but gave no indication of when the book would come out.

Rowling laughed at suggestions the new book was to be called "Harry Potter and The Pillar of Storge."

"I am trying very hard not to feel offended that anyone thought this was possible," she said on the site. "Storge, for crying out loud. Come on, people, get a grip." She was equally put out by the suggestion of "The Toenail of Icklibogg": "Well, if you believed the 'Storge' one..."

The five Harry Potter books have sold more than 250 million books worldwide, and the latest instalment - "The Order of the Phoenix" - sold 1.78 million copies on its first day in Britain. The success of the books has brought a major windfall for publisher Bloomsbury. "Harry Potter and the Prisoner of Azkaban", the third Harry Potter film, which opened in the US in early June, made $92.7 million (51 million pounds) in just three days.

"The Goblet of Fire" has commenced filming and is expected to be released in November 2005.

With such phenomenal interest in what happens to her fictional boy wizard, Rowling also teased fans on her website by saying more clues about book six would be gradually revealed.

The only hint she would offer was that the Half Blood Prince is neither Harry nor the evil Lord Voldemort. "And that's all I'm saying on THAT subject until the book's published."