The Washington Post had a live chat with Brig. Gen. Janis L. Karpinski, commander of the 800th Military Police Brigade and the person in charge of running prisons in Iraq.
Among the tidbits: Karpinski believes "the soldiers were given specific instructions and they had believed that the pictures were going to be used for another purpose in interrogation" and that the Nick Berg execution "was timed and staged before any of this came up and they (Zarqawi) just seized the opportunity."
Whole thing here.
Update: The plot at Abu Ghraib thickens. Elsewhere in today's Post, Secretary of State Colin Powell says there is no evidence (so far) of higher-ups giving orders while Sen. John McCain says there must have been.