Blizzplanet will giveaway two beta keys during the Diablo III beta gameplay livestream on Saturday, October 1 at 8pm CST (UTC -5) / 9pm EST (New York City).
Another two beta keys will be given away on Wednesday, October 5th at 8pm CST (UTC -5).
Blizzard Entertainment provided some beta keys to the Diablo III fansites. I'll update when I see any more. For now rush in and participate in the HunterStarCraft giveaway which closes tonight midnight (Oct 1).
HunterStarCraft -- D3 beta key giveaway (ends Oct 1, midnight)
Force Strategy Gaming -- Follow them. 7 winners will be selected Friday October 7th.
D3DB - Ends Sunday, October 2nd at 12pm (noon) EST
Diablo Fans - Caption Contest - holding 1 each week
I heard a dark whisper from the ether beyond Sanctuary. It said: "Grab one of the Diablo III T-shirts". Click-click-click-click-click ...