Books:

Book 6 will be titled 'Harry Potter & the Green Flame Torch'

Book 7 will be called 'Harry Potter & the Chariots of Light'

The last sentence will be spoken by Hermione, who says, 'Harry, what happened to your scar?'

JK Rowling said that the last word of Book 7 will be 'scar', however this could be changed due to editing processes (this matches with the above statement!)

JK Rowling has everything planned out, and so she has already written the last chapter of the last book. It is locked in a secret safe (imagine getting hold of that!)

Snape will fall in love with ... someone.

Fleur Delacour will be the next Defence Against the Dark Arts teacher, and may marry Bill Weasley.

Viktor Krum will return in future books.

'Time' might be the key to defeating Voldemort.

Something really big will be revealed about Harry's parents in future books.

Hermione will be made Head Girl (most likely!)

Draco Malfoy and Harry have to join as a team, and work together to defeat Voldemort.

Lucius Malfoy will be killed. (makes sense with the above statement, because Draco would be exceptionally angry if his father died, and so he would want revenge on Voldemort.)

Ron will go out with Hermione, and Ginny will become Harrys girlfriend.

Mr (Arthur) Weasley will be made the Minister of Magic.

Albus Dumbledore will die in one of the books.

The person who dies in the sixth book will be one of the Weasleys.

If you don't want any spoilers on the fifth book, stop HERE!

JK Rowling said that Sirius Black will be gone forever (he will not come back) and so we'd better get used to it!

However, rumours tell us that Harry will somehow contact Sirius through the Veil (a porthole between life and death) in the Department of Mysteries.

Luna Lovegood will go out with Harry.

Harry will be made Head Boy (?), and he is the heir of Godric Gryffindor.

Harry is also somehow related to Dumbledore.