The big news this week is that the level cap on the Mists of Pandaria beta has been raised to 90. You can go and explore Dread Wastes and Vale of Eternal Blossoms, but there isn't any raid content or Pet Battles, and some of the scenarios and Battlegrounds are not yet available. At the time of writing this, the premade template characters were not available yet for level 90, so you'll have to climb the level ladders the old-fashioned way right now.
I'm sure you're thinking that it took long enough, but to be honest, this is a bit sooner than I anticipated. While we've seen the talents, we haven't have the chance to work with them quite yet. Now, we finally get to dive in and play with them, experimenting for what will be our best choices in any given situation. It's like unwrapping a brand new toy for the first time, and I'm pretty excited.