So, I have the skyrim disc in my pc as we speak.
I logged in on Steam, entered my cd key, skyrim appeared in my games list, but I got a message saying it can't be installed and now skyrim is all greyed out on Steam. What gives ???

It's not the 11th.

Even *if* somehow you got it early, you still can't play it until Friday

This.

You will have to wait until Steam unlocks your game.