The choice as to whether you're Alliance or Horde doesn't happen at character creation, though. The choice will come after you've played through the introductory quest chain for your character. Once the stage has been set and you see where the lines of war have been drawn, you will choose which faction represents your interests best. Exciting? Oh, yes.
Turn to WoW Insider for all your BlizzCon 2011 news and information. Look for our liveblogs of the convention panels, interviews with WoW celebrities -- and of course, lots of pictures of people in costumes. It's all here at WoW Insider!