Well, a Multiplayer demo was announced to be released on September 11th 2009, but still no details on what it will hold, or when the actual game is coming out. There have been rumors that D3 will be released before StarCraft 2, but again, the last press release from Blizz says the same as always "The game(s) will be release when they are ready".
source :
blizzard.com
