In the meantime, while you're waiting, you could always look at our Patch 5.0.4 coverage or find a book on the Kindle store (I know of a good one) to read.
Edited to add: maintenance has been extended until 3:00 p.m. PDT.
As of 2:50 p.m. PDT servers appear to be coming up.
It's open warfare between Alliance and Horde in Mists of Pandaria, World of Warcraft's next expansion. Jump into five new levels with new talents and class mechanics, try the new monk class, and create a pandaren character to ally with either Horde or Alliance. Look for expansion basics in our Mists FAQ, or dig into our spring press event coverage for more details!