There should be casting news this month or next, if it's already gotten out they offered the part to Daniel Craig. This is such a challenge; I think it's harder to cast someone to play Thor or Captain America, than Superman or Batman...
I also think back to the casting announcements we heard when LOTR was getting started. And how I scratched my head about casting actors like Elijah Wood, Ian Holm & Sean Astin to be Hobbits(as they were not dwarfs or midgets.) But then we saw the subtle FX work on the big screen and how it worked so beautifully. I have faith that Marvel with get Thor onscreen looking as close to the comic page as possible.