A NYT article and a corresponding tweet by Neil Patrick Harris are more than enough to confirm it.
Whoopi would be interesting. My issue with Colbert is I wonder how seriously he'd take his duties. Part of the problem with having a comedian host who is actually funny can mean that the show itself can be upstaged or feel more like an afterthought. That's why I like someone like NPH (though I want someone different.) Yes, he's funny and entertaining but he doesn't have the potential to have some sort of uproarious skit or antics that will upstage the whole show and ultimately the performers and all of the nominees, the people who the show should ultimately be about. Whoopi could definitely pull that off. I think Ellen Degeneres could be fun too, but there's no point making suggestions if the Theatre Wing has already decided.
Scratch and claw for every day you're worth!
Make them drag you screaming from life, keep dreaming
You'll live forever here on earth.