This is a easier poll than the "When will Wii outsell PS2" thread since Wii is a long shot from PS2 numbers but failry close to PS1 numbers (102 Million).  I think if Wii does very well this year, meaning topping 2009 numbers I can see Wii topping PS1 late 2011 to Spring 2012. 

end of 2010 - 83M

end of 2011 - 95M- 98M

end of Q1 2012 - 101M- 103M

Late 2011

Yes, this one's more likely... I'm thinking late 2011 too.

With one or two "phenomenon" games - like wii fit or wii sports - maybe even sooner

If Wii shipments hit 85M end of this year, Wii will only need like 15M to be around PS1 numbers.

Wii won't outsell the PS1. Has too much ground to make up and the next Nintendo console shouldn't be too many years away.

You should've put the option "never", just in case a meteor hits Nintendo HQ.

I didn't put that down since I knew people will just vote for it for the sake of it.  I'm quite optimistic and assume that wont happen to Nintendo HQ.

RageBot, on my behalf, let me apologise for Nintendogamer

Figuring ~20m a year for Wii means it should be ~90m by end of this year and given that most sales occur at year end, I picked late 2011 to catch PS1.

However, things could go either way. Wii could have stellar years of 25m+ or could slow down more to 15m or less. I'd think it would stay above 20m this year though.

So far Wii is treading just above 2009 numbers which has a totla numebr of around 22M, I think WIi has a good chance at staying above 20M this year.