The title is a bit misleading, because the PS3 has already outsold the 360 in worldwide sales several times this year. If you mean, will it happen in the final nine weeks of the year, that's a different question entirely!
In short, I don't expect PS3 sales to pass 360 sales worldwide at any point before 2008. This past week, the 360 outsold the PS3 by about 75k units worldwide (180k to 108k); that's a pretty sizable margin, approaching double the PS3 number. Since the PS3 is not going to outsell the 360 in the Americas region this year (I hope we can all agree on that...), it needs to make up the difference in Europe and Japan. The PS3 price cut has already taken effect in Europe, and sales if anything should be declining slightly over the next few weeks, until the holiday season sees everyone's numbers rise. There's simply not enough difference between the two systems in Europe to affect the overall totals in a serious fashion. And although I expect PS3 sales in Japan to go up significantly for the holidays, Sony just isn't moving enough systems there either to make a sizable dent in the 360's Americas lead.
In other words, while it's certainly possible, I don't think it's likely to happen. If the PS3 had a huge holiday title releasing in the next few weeks to boost hardware sales, it would be a different story.
End of 2008 totals: Wii 42m, 360 24m, PS3 18.5m (made Jan. 4, 2008)
