All the stores around here have the Wii in stock now, though they were out over the holidays.
I can understand Nintendo's troubles. You plan for a certain sales point and ramp-up production to meet that goal. If the product's demand greatly exceeds your prediction, you will be unable to keep up and then you have to try and guess if the huge demand is a momentary spike or will it be sustained. You don't want to spend a ton of Yen on additional production facilities, only to have them sit idle once they're ready because the demand has disappeared. If it's a spike, you ride it out with existing production facilities and catch up when the spike is over. If it's a sustained demand, like the Wii's appeared to be, then you're going to want to add the additional production capability ASAP.
I understand there is a huge demand for crystal ball operators in most corporations today. Maybe some of these people who are criticizing Nintendo would consider applying for the position, seeing as they obviously saw what Nintendo didn't before it happened.