It appears that BioShock has changed it's release date to today. There has no been any official conformation from Microsoft or Take Two and neither of their PR agencies are available for contact. However, many things are proving that this is true.
1. Toys R' Us in the United States has been selling copies today
2. The commercial now says "Available Now" and this has changed from when I saw the commercial 2 hours ago
3. The game is driving the hype train after the demo and it would be smart to release today
4. Ken from 2K has confirmed it (conflicting, may be false) // it matches with the commercials I've seen though
I am personally trying to contact every gaming related person that would have knowledge on what's exactly happening. But chances are we will get a press release later tonight or early Wednesday morning.
In Canada, these commercials can be easily spotted from the earlier ones because they also advertise the 360 price cut after the commercial. [I'll try to tape it next time around]
UPDATE: I have just gotten somewhat official information that the game will be sold through every store as of now that already has stock of the game and they will be shipping the game rapidly to all stores. They have advised that there will be alot of confusion among retailers and that due to these issues, you may not be able to get your copy until things have been cleared up.
I checked Amazon, Best Buy, Circuit City, Best Buy Canada, FutureShop and Walmart online stores and all dates are still indicating 08/21/07. I would guess this will be mixed by the morning. I can confirm for a fact that the "Available Now" commercials are real since I have seen them with my own eyes.
More Information as I get it! // Btw, I still haven't seen another commercial and it's around 12:33AM in Toronto. Hopefully one comes soon.