I'm not sure what Sony's plan in this fight is. They slightly missed their goal of 2 million PS3s shipped by the end of 2006, then got scared and changed their prediction of 6 million PS3 shipments by the end of March to just 4.5 million shipments instead. Since then, Nintendo has continued to fall behind the voracious demand for their Wii console, and have achieved a substantial early lead over the PS3.
There's talk that Nintendo already reached 6 million console shipments, but if demand is really that high, then the number of shipments should equal the number of sales, and according to VGCharts they're still a little short of their six million goal. It also lists Sony at barely beyond the 2 million PS3 sales it reached in January.
How about that chart of videogame console sales? Here it is, and it's pretty rough.