This isn't exactly a new story. Amnesty and other alleged human rights groups have been saying this for at least a year now.
There have been allegations that these so-called secret prisons existed, but this is the first detailed quasi-confirmation that they do. I think the leak is coming from the Dems on the Senate Intelligence Committee. I wonder if the secret session of the Senate yesterday touched on this matter and its publication in the WP. I assume Dana Priest contacted various USG official to confirm the story and give them a heads-up about its publication today.
"But Guantánamo may not be the worst problem; indeed, it may even be a diversion from more extreme situations. Perhaps out of concern that Guantánamo will eventually be monitored by the U.S. courts, the Bush administration does not hold its most sensitive and high-profile detainees there. Terrorism suspects like Ramzi bin al-Shibh and Khalid Shaikh Mohammed are detained instead in undisclosed locations outside the United States, with no access to Red Cross or other visits."