Jason Kottke has a lot of links to videos and photos of this nightmare.

The latest footage I just saw on CNN chilled me to the center of my being; you can see the jet liner slice right through the tower. And parts of it keep on going. I keep thinking about the terror those passengers must have felt in their final minutes.

The bastards knew what they were doing. They deliberately chose flights that were going to the west coast, since they would be filled to capacity with fuel; the bellies and both wings would have been full. They turned those jets into gigantic bombs.