You're not alone.
Battle.net authentication servers are down, or at least very, very slow to respond. Blizzard is working on a fix, however, so it's only a matter of time until they come back up. We have heard reports, though, that people are able to get in occasionally.
In the meantime, I invite you to do what I'm doing on Twitter: tweeting my useless authentication codes as the time goes by. Also, I invite you to enjoy the above image, made for us by Fox van Allen. Why? Because it's better than staring at the WoW login screen.
Update 9:33 p.m. EDT: Blizzard has tweeted that the problem has been resolved. But you still get to enjoy that pic, so it's a win-win-win for you!