I've been seeing quite a few threads lately asking the question "When will the PS3 outsell the 360" so I decided to estimate things using the sales for 2008 so far as a template. Of coarse it may not be 100% accurate due to price drops or new releases but I'm sure It will pretty close. I'll start with a hardware table:

VGChartz Hardware data for the period 05th Jan 2008 to 01st Mar 2008:

As you can see there is a difference of 507,685 consoles in this 8 week period which shows the PS3 at an advantage. If we divide that sum by 8, we find it is outselling the 360 by 63,460 consoles per week. The next step is to take the lifetime difference in sales up to March 1st between the two consoles

The difference is exactly 6,749,858 consoles.

If you take the equation 63,460(x weeks)=6,749,858 then you get 106.36 weeks which equals 2.03 years from this point or March 10th of 2010.

There is one more thing to take into account, and that is the holiday season. What we'll do is take the average sales per month of 2007 of the first 11 months and factor in how times more consoles are sold in December than normal.

VGChartz Hardware data for the period 06th Jan 2007 to 24th Nov 2007:

If we add the sales of the two consoles together we get 11,083,293. Now we divide that sum by 11 for the average combined sales for non-holiday months and you get 1,007,572 consoles. Next we take the holiday sales for 2007.

VGChartz Hardware data for the period 01st Dec 2007 to 29th Dec 2007:

Now we divide the holiday month sales by the normal month sales to find out how many times more consoles are moved for the PS3 and the 360 in December. 2,408,423+2,303,356=4,711,788 in combined PS3 and 360 sales for december.

Now we divide december sales by the average non holiday sales per month and we get about 4.68. That means that during the holidays about 4.68 times more consoles are moved per month. Knowing this we take the holiday season for '09  Which is a 4 week period where the PS3 outselling the 360 by 4.68 times the normal amount of 63,460 and we get a difference in sales of 1,187,971.

Once again we go back to our original equation:63,460(x weeks)=6,749,858.  We subtract the difference in sales for December (1,187,971 units) from the total differnece so far (6,749,858 units) and we end up with 5,561,887. Now we apply this number to the new total to find out how many weeks it will take once again. So, 63,460(x weeks)=5,561,887 Divide on both sides of the equation by 63,460 and we end up with 87.6 weeks or 1.69 years from march 1st. Therefore you should expect the PS3 to outsell the 360 in early November of 2009. I could give the number of consoles sold up to that point as well, but that would be an even larger burden than this was so I hope you're happy for now.

Once again the Conclusion: Early November of 2009. 

Wow, good estimate.....I think it might be 2010ish

wow... i could never do that kind of math or predictions w/e

good estimate and i predict mid 2009.

welcome to teh site btw

Awesome... *awaits PS3fags for doubts*

nice job

My signature is what I believe will happen.

 Quoted for Posterity.

Not sure about what I think on how it'll actually turn out... I just wanted to say thanks for taking the time. That was interesting.

YOur good at maths.,lol

Good numbers, but are we all assuming that either console will keep selling at this pace forever?