Can they actually manufacture that many units though?

 That may be the only reason they won't pass the 360 this year.   All I have to say, by the end of the year, 360 and Wii will be fairly close to each other with total units sold.   Have to see what the Halo and GTA effect will do to consoles sold. 

wii will outsell the 360 before the end of the year. PROUD PSWII60 Owner

The absolute earliest the Wii could surpass the 360 worldwide is in July. March 31st, 2007 - 5.84 million Wiis. If they increased shipments to 1.2 million Wiis a month, this is how it would work out (at full sell out). End of April - 7 Million Wiis End of May - 8.2 Million Wiis End of June - 9.4 Million Wiis End of July - 10.6 Million Wiis This is ONLY if they sell EVERYTHING they produce. And this is assuming the 360 is sitting by each month doing nothing, which isn't the case. Being modest, the 360 should sell at least 300,000 consoles a month Worldwide, so, taking VGCharts numbers: End of April - we'll say 9.4 Million 360s End of May - 9.7 Million 360s End of June - 10 Million 360s End of July - 10.3 Million 360s So, July is the absolute soonest, unless someone can give me definitive reasons why the 360 would sell less than 300,000 a month and the Wii will sell more than 1.2 million a month?

Nintendo's forecast is 20 million units sold by March 2008, so you'd expect they could manufacture at least that much. This alone should put them at around 17 million by year's end. Plus, also according to Nintendo, this is not the production limit. Yeah, they can manufacture that many units.

Now I know there is the fad argument, but fads are when the novelty can't be expanded upon. The Adkin's diet coulnd't reinvent itself when it turned out it wasn't an easy way to lose weight*. Beanie Babies coulnd't just magically rebuild the bubble when their market fell. However, the Wii can have more games when people are done with one game, as happens with EVERY successful system.

 *And the Adkin's diet was just meant as a way to kick start a slow metabolism (so some people didn't even need it), not a long term dietary change. So people were doing it wrong anyway.

Great analysis! 

Not knowing what the actual production capacity is (I believe it's a little lower at about 1M a month and will ramp up towards the end of the year) and if demand will eventually be met with that number, I don't think we'll see the Wii pass the Xbox 360 until August at the earliest.  And by then the Halo 3 effect may increase Xbox 360 sales to keep the Wii in second place until later in the holiday season. 

Of course it's not a matter of 'if' at this point, it's just a matter of 'When will the Wii will pass the Xbox 360 in worldwide sales?'

The question remains: Can the Wii, with it's big titles and growing user base be able to compete with Microsoft's big guns.