[MysticCat]

Actually, I think it was more that flames burst out around him, and his tomb appeared from the flames. A white phoenix rose from the fire and flew away -- that was his patronus.

I think Dumbledore is indeed dead -- on the next great adventure, if you will. JKR has made it very clear; in the heroic genre that she is following, the hero must at the last go on alone. Think, for example, Luke Skywalker having to go it without Obi Wan Kenobi; Frodo Baggins having to go without Gandalf. (Of course, Gandalf did come back from the dead, but he did not return to Frodo.)

I think we will still "hear from" Dumbledore. His portrait will be in the headmistress's office, and he may have had other ways of preserving his memory. (Might Harry spend some time with Dumbledore's bottled memories in the Pensieve?)