well xbox is still raping in the US, and its always very close to ps3's numbers, so even if there were shortages. it just seems very odd that there would be more than a million more ps3's on selves than xbox's
MS is selling inventory as retailers receive shipments. They are temporarily unable to stock up to regular inventory levels. Retailers are stocked up with the appropriate number of PS3's.
Remember, the 360 shortages, just ended, there hasn't been time for retailers to stock up 360 consoles. 360 outsold the PS3 from Sept-December by about 1 million units, it doesn't make sence for the shipped difference to only change by 0.08 million units.