I saw a thread about someone getting their call from GameStop saying their copy of the game was ready but I haven't received one and I do my GS is having a midnight launch. I've never been to one and don't know what to expect, any help is appreciated.
They will tell you when they open (usually 10PM) then you just go in any time between then, and midnight and pick it up, and walk out just like any other game.
Its simple. Go sometime during the day to finalize your purchase. Then when you show up at midnight (you should get there before) show them your receipt, they give you the game, and you go home to play.