Dustin Browder, lead designer on StarCraft II at Blizzard, says that the team is planning to have a publicly playable beta for the game that runs about "four to six months." When that would go live, Blizzard still isn't saying.
But considering that we're already six months into 2009, a four to six month beta period is kind of cutting it close, if the game has any intentions of shipping this calendar year. Granted, Blizzard hasn't officially committed to that, but StarCraft II: Wings of Liberty is the company's best bet for a "front line release" this year. So... will it ship this year?