To basically copy and paste what I said in the other thread as to how I think they may meet this goal:
I think continued momentum from the drop to $299 will help a long way towards getting to there, then a drop to $249 in anticipation of Move plus the release of GT5 will help cover what they have left over.
Remember, the ps3 was doing pretty poorly last year at $399, and it is doing remarkably better over the start of this year. The ps3 has thus far sold 3.6 million units this year, compared to 2.6 million units over the same period last year. That's a 38% increase. Assuming that holds true through the end of August (release of Slim last year), that would see the ps3's sales increase from 4.22 million last year to 5.82 million, well before the holidays have even begun.
Toss in a small price cut and GT5, and you'll probably see similar holiday sales to last year, followed by a weaker first quarter due to a lack of anything on par with God of War and Final Fantasy. Given all this, I could see them landing near 15 million total - 15 million sold, but that'll translate into shipped.