BBC Field reporter about the US Flag that was temporarily placed on the face of the Saddam statue yesterday:

] We've just learned from the US marines that the US flag
] that was put on the face of Saddam yesterday - it was
] replaced by an Iraqi flag when the people shouted for
] that - was the flag that was flying over the Pentagon on
] September 11.
]
] For a lot of the American marines, they think this war is
] all about defeating terrorism, they will tell you that
] over and over again. There is also a connection in the
] minds of the American public between the regime of Saddam
] and what happened on September 11, and apparently the
] flag that was draped over this face was flying over the
] pentagon when the plane crashed into it.

Note: I haven't been able to find any confirmation of this story aside from the BBC report.

Update: ABCNews is confirming this, in an interview with the soldier who put the flag up, Corporal Chin from New York:
"And the flag — it was on the Pentagon when it got hit on 9/11. That was the same flag, and me being from New York, it kind of all goes together a little bit. It was a team effort, which made it even better, you know," he said.

ABCNews article here:

 http://www.abcnews.go.com/sections/GMA/Primetime/Iraq030410USFlagStatue.html

Further update: Other news agencies are confirming that it was Marine Corporal Chin up there, but are not mentioning the origin of the flag.