The Washington Post has come out with a bunch of new articles over the past few days on Abu Ghraib, based on the statements of the soldiers involved, and allegations by one of their lawyers that Gen. Sanchez, the highest-ranking officer in Iraq, knew what was going on, and had in fact witnessed one or more of the interrogations.
On the one hand, I'm perfectly willing to believe that people farther up the chain of command encouraged these kinds of interrogations. On the other hand, it seems pretty clear that at least some of the soldiers were enjoying themselves, whether they were "just following orders" or not. From Spec. Darby, the soldier who originally discovered the photos and reported them to his superiors:
[Darby] said that he asked Graner, a Pennsylvania prison guard in civilian life, about the photographs. Graner replied: "The Christian in me says it's wrong, but the corrections officer in me says, 'I love to make a grown man piss himself.'"