A friend of mine pointed me to this post on LiveJournal.com:
http://www.livejournal.com/users/fabularasa/27100.html
I agree that Dumbledore did in fact die, and that he had an agreement with Snape for Snape to kill him.
However, I wouldn't be surprised if in book 7 he contacts Harry somehow and explains it all to him.
I think this is one of the reasons Snape treats Harry so bad:
Snape and Dumbledore are/were in cahoots over Voldemort's demise, but Snape always get the short end of the stick, because he's an ex-death eater. To top it all off, the guy he has to help is the son of the guy who tormented him throughout school. Basically, "I ruin my life and career for
this kid??"
Ah well. Now we wait another two years to find out.
Dave