I've been trying to hunt down a Wii for the last week or two. I read some arguments on the internet that the Wii is only outselling the PS3 because of the quantity available i.e. Sony would outsell had they the inventory.
The funny thing is that I don't think that is the case. Everywhere I've been for the last few weeks never have any Wiis in stock but they always ask if I want a PS3 because they have a bunch of those. I've seen them in nearly every store that sells videogame hardware but the Wii is absent.
Given this observation it appears to me that had the Wii and Sony both had enough machines to meet demand then the Wii would still be crushing Sony. There's less available but I don't see them so brutally sold out the way the Wii is.