If you have ready access to a computer, then definitely w/o a doubt sign up for Wiialerts. This is how I bought ours. You literally have 2-3 minutes to order from the time you get the alert on your phone.
I ordered my Wii about a week from the time I first signed up. Anytime a site gets them instock, you will get a text on your phone. You'll get an email too, but sometimes there is a bit of a delay due to firewalls, server, etc.
This was WAY easier than stalking the stores, calling every day, etc.
Don't buy one on eBay, you will pay way more than retail.