This entire story has been revised by Dumbledore.
A while ago, Bulgarian website
Novinite posted news about the book 6 title, and added that it was "due to appear within 4-5 months".
Quote:
Harry Potter fans will be able to devour the next adventures of their favorite hero in their sixth book by JK Rowling due to appear within 4-5 months.
This was PURE SPECULATION on their part and is in no way to be considered truth.
The facts are overwealmingly clear that
Book 6 (HBP) is at least 7-9 months away. Maybe even longer.
Reasons we know this:
1. JKR has said she is barely finished with the FIRST DRAFT.
2. The title for book 5 (OotP) was announced over a year before it's release.
3. For OotP, JKR and her publishers announced that the book was finished 4 months before it was actually released. Since JKR is only finished with the first draft, there is no way she will finish the book and hand over the manuscripts within a few days.
Sorry to disappoint everybody but the fact is
we shouldn't expect Book 6 before 2005. It is
possible that she could complete the book within 3 or 4 months, which would make a Christmas release possible, but this is highly unlikely. My bet is April 2005 or later.
We assure you that we will post a closer time-frame for when to expect the release as soon as JKR announces that she is finished with the manuscript.
Thank you!
Note: All comments up to Marcella Riddle's are based on thinking we announced that it was possible that Book 6 could be released in 4-5 months. It is NOT POSSIBLE, so I (Dumbledore) had to revise this entire story. Sorry about any confusion! 
