Sadly that site only covers the US.
The Wii is hard to find all over the globe. In the Netherlands they are nowhere to be found. (most local stores here are now advertising Gamecube instead) :-/
My friend was looking for a Wii and like a true geek he found a way for the web to find one for him. This web site OuttaStock tracks the availability of whatever you want and you can get the updates via an RSS feed. Very cool Here's the link to the Wii watch: http://www.outtastock.com/wii/
For Mac geeks like me there's a Wii Finder Widget that will notify you if any are available in stock (http://www.outtastock.com/wiiwidget.html)
Also, check out the history. Those things are FLYING off the shelves.