I'm not surprised nor am I impressed by this.
In America, the Cash for Clunkers program that gave tremendous rebates from the government (on taxpayer money) to people who traded in their old cars for new cars caused something of like a 600+% spike in autosales in the month of August.
Sony cuts their console's price down to the same amount as it's competitors, along with releasing something new (the PS3 slim... and we all know there are folks out there who just GOT to buy the newest thing on the first day, for instance the DSi) and so it's only logical that Sony sold a considerably larger amount, of course while taking a loss on every single one being sold.
if you sold 200 hamburgers in a month then you cut your price from $5 to $2 taking a $3 loss but making your burgers as cheap as your next competitor, and then sold 1,998 hamburgers the next month, thats a 999% increase in sales.
So ultimately, it'll be more interesting to see the next few weeks in sales.
Also this was only reported in the UK... not North American sales, from what I understand.