The New York Times is also on this story, though they aren't willing to go as far with it as CBS has:

Britain, the United States' staunchest ally in its campaign to disarm Iraq, has begun to distance itself from the White House's insistence on confronting Baghdad with or without the United Nations' blessing.

So, it's not that Britain is pulling out. But they are sending signals to Bush that, if they don't get the UN resolution, the United States might have to go it alone. Not that that would bother the PNAC crowd. In fact, they'd probably like it. All the less glory to share and all the better to demonstrate to the world that we can make them obey all on our lonesome. Thus Rummy's initial shrug this afternoon at the news that this might happen. And once again proving to the world that, while Bush may screw his enemies, he will screw his friends even harder.