Bruce Schneier has an extensive collection of links regarding the TSA and current screening procedures.

One thing that seems to get overlooked in all of the stories I’ve read, in which some government official insists that the ever-more-invasive security protocols are needed, in order to prevent attacks like the shoe bomber and Christmas-day bomber, is this: these protocols never would have stopped either of those attempts, because neither passenger boarded a flight originating in the US. They are being used as excuses.

The government says, “Trust us. We need to do this for your safety.” The problem is that the government has no credibility. There’s no incident of a bombing which could have been prevented by these scanners to which they can point, and no statistic of risk they can cite which they could improve upon. They promise that the scanner images aren’t retained, but then we discover that’s false. How could it be true, anyways? The government isn’t going to hang on to potential evidence in case a passenger needs a followup pat-down, or there’s a subsequent problem on a flight? All they have is a manufactured fear they keep promoting.