The last book of the Dark-Hunter serie by Sherrilyn Kenyon is released on 07/08/08.
It's in pre-order in amazon and play.com. The best price is in play.com, with free delivery at 11.49€ (http://www.play.com/Books/Books/4-/5446759/Acheron/Product.html#).
The is published by Piatkus Books (in United Kingdom) and as 736 pages in paperback.

The review says:

Eleven thousand years ago a god was born. Cursed into the body of a human, Acheron endured a lifetime of hatred. His human death unleashed an unspeakable horror that almost destroyed the earth. Brought back against his will, he became the sole defender of mankind. Only it was never that simple...For centuries, he has fought for our survival and hidden a past he never wants revealed. Now his survival, and ours, hinges on the very woman who threatens him. Old enemies are reawakening and uniting to kill them both.

Born: 9548 BC
Birthplace: Atlantis or Didymos (depends on who you ask and how Ash feels when he answers)
Motto: Just because you can doesn't mean you should.
Favorite Song to Hunt by: Awake: Godsmack
Current Location: Constantly moves, and we make weekly bets on where he is or where he'll turn up.

 More in: http://yearofacheron.com/acheron.html