OK, if you really, really want me to ruin the ending.
Dumbledore does die near the end of Book 6, and Harry sees him die. He is killed fighting the Death Eaters, by none other than Professor Snape (using a curse) having been weakened earlier by a potion he drank. When the book ends, Harry has to go into hiding and Hogwarts looks like being taken over by Snape.
However, you have to wait till Book 7 to find out what really happened...
Dumbledore does die near the end of Book 6, and Harry sees him die. He is killed fighting the Death Eaters, by none other than Professor Snape (using a curse) having been weakened earlier by a potion he drank. When the book ends, Harry has to go into hiding and Hogwarts looks like being taken over by Snape.
However, you have to wait till Book 7 to find out what really happened...