As you can see, there is still some 10-man testing left, but it's going on right now, so log onto beta servers quickly if you want to participate.
If you're wondering how on earth you'll be able to get a group together on beta tomorrow to do a 25-man raid, I can assure you there have been plenty of trade chat groups thus far that you can join. Many of the groups are guilds who don't have their entire roster on beta, so they have to pug additional players to fill their raid groups.
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!