I just got back from picking up my copy of 'Bully' ('Bully' walkthrough) at a Game Crazy. I asked the store manager if he knew when Wii pre-orders would begin. He said that the rumor is that Nintendo is today telling Game Crazy how many units Game Crazy will be getting. Then, over the next two days, Game Crazy will determine how many each store will get. Then, on Friday or Saturday, the pre-orders will begin.
The store manager (who shall remain nameless) said that he has heard that each store should be getting around 40-50 units each. There are about 700 Game Crazy stores, times 50 units each, equals 35,000 units going out to Game Crazy. That's a mere drop in the bucket for the supposed 1 - 2 million Wii expected to hit the streets. For comparison's sake, there are 3,600 Gamestop/EB stores out there. Assuming the same allocation, that's 180,000 units. Together, that's about a fifth of the Wii launch day shipment. Conclusion? There's a good bet that you'll be able to go into a Best Buy, Circuit City, Kmart, Walmart, etc. on the day of launch and get a Wii.
Keep in mind, this is how my Game Crazy is doing things. Other lunabeanies have told me that their Game Crazys have been taking pre-orders for months. So, check in with your Game Crazy near the end of the week to see what's a happenin'.