Universal has just released six screenplays online right here. They're the ones the studio is hoping will get a Oscar nominations - well, presumably they're hoping for an Oscar win but steady on - so they're arguably the pick of the bunch.
They're all the shooting scripts so none of the rubbishy tarted-up transcripts you so often see published and they're all in PDF format. A personal favourite is there, The Bourne Ultimatum, which I'm planning to read as soon as I've stopped talking to you. But there's also American Gangster, Breach, Elizabeth - The Golden Age, The Kingdom and Knocked Up.
I didn't know this but Paramount Vantage, kind of the arthouse end of Paramount if there is such a thing, has already done much the same. If you haven't seen it, here's Paramount Vantage's collection of scripts.
You will notice that Jason Arnopp's screenplay, Look at Me, is not yet available online anywhere but this will surely be remedied soon.