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.

(unconfirmed) US Flag on Saddam statue was the one that was flying over the Pentagon on September 11th