Let's avoid another one of those Ant Man posts, shall we. Here's video of Joss Whedon confirming quite clearly that yes, Jeremy Renner has been cast as Hawkeye and he will be in his Avengers movie.
The confirmation comes at 1:25, and he says:
I don't have all the news. I think it's well known that Jeremy Renner is joining us as Hawkeye which is so exciting for me and the rest of the cast, and we haven't finalised anything else I can talk about. But I do think I am putting together and extraordinary power house cast and I'm just so excited to be in their presence, and I just hope they don't kill each other.
He's going off message there, I think. Wasn't it just Ed Norton that was going to lead the cast to murderous violence? Marvel: quick, fax him another script.