From the New York Times.

So we're supposed to believe that there were vast organized teams of "looters" ready to go in Iraq if we invaded, with trucks, heavy equipment, and all the rest. We're supposed to believe that they would loot primarily weapons sites instead of commerical factories and other sites with things of great value on the black market.

There's a much simpler explanation. That this was a pre-planned effort of the Iraqi government designed to destroy or move anything loose related to weapons work.

The article raises many interesting questions, chief among them why a completely non-existent weapons program would have so much weapons-related stuff lying around.