It's a shame that NexGen Wars can't keep correct information. Even while going through numerous sales, Nintendo shipped out more than 600,000 consoles to US stores before Day 1. Since I have not known one of those stores to have even one remaining Wii, Nintendo would have sold over 600,000 consoles the first day.
Though yeah, I have a friend that now has a Wii. I'll explain more in a bit - via Edit