joeorc, as of last qtr, Sony had sold 4.28M to retailers (their financials). Typically, the sales to consumers are a bit less than sales to retail.
The 6M no. quoted was warehouse shipments (marketing message, thus the biggest possible no. was chosen I guess).
Btw, vgchartz is fairly accurate with their estimates. Example:
http://vgchartz.com/forum/thread.php?id=5078
So, if sales now are ~ 4.6M, sales to retail would be ~5.5M
