Why is this a news story?
Seriously, what did you expect? When a new product like this hits the market you're going to have the majority of people who want to buy it picking it up immediately, and you'd expect a huge drop-off for the second week. For a perfect product with no supply constraints whatsoever, everyone would buy one the first day, and sales would then drop 100%.
The first week sales were record-breaking (which was, of course, utterly meaningless). The second week sales are still pretty good - 30k units in a week in the UK market is good sales. There's not going to be anything worth talking about with sales figures until a good few months from now once we're over the launch highs and lows, none of the systems are supply constrained, and we can see their regular ongoing sales.
Just to give you a reference point for how ridiculous it is to see this as some sort of disaster, if the PS3 continued to sell at the same rate as it did in its launch week (165k units across two days) then by the end of the year it would have sold over 20 million units in the UK alone. Don't you think some sort of drop-off might have been expected?