Do not believe any advertised release dates. Do not pre-order. Wait until you can see a physical copy of the game at a store!!!
Sorry... I too am anxiously awaiting SC2's release and it's crazy that it's been in development for so long and keeps being pushed back.
play.com has a june 2010 release date on their website, but it means very little becaue gamestop, bestbuy, and other places have had release dates up for it for the past couple of years and they constantly change.