Some of you are experiencing some major trouble getting on and without a doubt it's frustrating. Many servers are up right now at 7:30 P.M. EST time and many servers are still down. Heroic ToC opened up and yet many guilds can't get in to access the content. There is hope though. In the latest forum post Blizzard has said it shouldn't be more than two more hours. Will it take longer? Let's hope not.
So if you're still waiting for your server to come up just chill out, read up on the heroics, and wait a little bit more.
Edit: More servers are coming up in waves. Yay!