On December 21, they announced that the 7th book to Harry will titled Harry Potter and the Deathly Hallows. 
The release date has not been set yet but J.K said herself that it is "LIKEY" to be released my May of 07.
This will be that last Book for Harry. 
I'm still trying to find out more to keep you all posted.
P.S. If you find out any info can you post it here PLEASE.