Seeing as how I keep a part time job on the weekends there for the store discount I can bring some good info for you on this. Best Buy should be receiving their shipments of the game on Monday evening (all WA Best Buy stores receive shipments on Monday and Friday nights, not sure about other states.) and have it available on Tuesday morning. As far as specific dates, Best Buy computer systems have a hard street date of November 23rd. I'm willing to bet that they will have it by that date, but there have been times where dates have been pushed back by weeks/months/years (*coughhalf-life2cough*)
Hopefully Blizz will have more info up on the Open Beta soon, I'm going through withdrawls from not being able to play closed beta anymore. I had requested a weekend off and they finished off the closed beta, haha.