Update: Atlantis is now orbiting the Earth. There was some concern on ice in one of the Auxiliary Power Units, but that seems to have been taken care of. The Shuttle is on its way to the Space Station to deliver a new piece with solar panels that will greatly increase the power capabilities of the station. Read more about the mission here.
Update: 2:30 minutes to launch. Things look good.
As I write this, Atlantis is just 4 minutes to launch. Watch it live!