Since people are asking, yes, Paul Sams did announce during the closing ceremonies last night, before Tenacious D came on, that 1000 of the attendees at Blizzcon would be randomly selected to win a Diablo III Beta key. He built it up amusingly, saying, “I have three special words you’re all dying to hear.”
Fans shouted out, “I love you!” “For the Horde!” and other such suggestions, before Paul finally went with, “Free Beta Keys!”
There was actually considerable booing at that point, as everyone wanted a beta key, rather than a 1/25~ chance of winning one. But Paul pressed boldly on.
He did not, however, give details about how the winners would be selected or notified. There’s no way we’ll miss it, though. Blizzard doesn’t sneak beta tests past us in the night—they give plenty of advance notice of the tests and the sign up times, and we’ll (of course) post notice about those here when it happens. Check the Diablo III beta article in the wiki for many more details and a FAQ.