Blizzard has updated their Under Development (http://www.worldofwarcraft.com/info/underdev/) page with some of the features coming in 1.8, as well as a Silithus preview (http://www.worldofwarcraft.com/info/underdev/1.8/silithus-intro.html)!

Read more, and discuss this here (http://wow.forums.thedruidsgrove.org/showthread.php?t=9346).