Blizzard's Technical Team, Is working as diligently as they can to bring the realms back online with the arrival of Patch 4.3. However, They also have to ensure no problems will arise once the realms are brought back online.
I understand that this can be a complicated process and can take some time. So, We'll need to wait until the realms are brought back up or if additional maintenance is needed.
I understand this completely, and as an Arizona citizen, I understand it will not be up here until noon or later. However I tried to sleep in this morning to aid in the waiting process, I was too excited and awoke at 8:30 this morning. I am Patient and understanding, but it does not make me any less eager to play with my new toys.. *chuckle*