Author Christie Golden has posted a little more information about the Arthas novel coming next year -- she lists the release date as April of 2009 (Arthas will probably still be alive then -- if "alive" is what he is now), and says that it'll be a nice hardback edition, which should be cool to see. She also says that while they were considering throwing a sample chapter in the BlizzCon goodie bag, all they were able to get in is a little postcard art of the book's cover. Too bad -- it would have been fun reading a little preview of the book while waiting in line to play, say, Diablo III.
And for the Starcraft fans, she's also got a Dark Templar book coming out a month after that, in May 2009. It was supposed to be out sooner, but apparently Arthas' book got pushed forward, and she had to switch up schedules a bit. So two good pieces of extended universe fiction for Blizzard's games to look forward to next year.