The WashPost has posted a Reuters's article that NPR has reported that coalition forces have found chemical weapons in Iraq (got that?):
NPR, which attributed the report to a top official with the 1st Marine Division, said the rockets, BM-21 missiles, were equipped with sarin and mustard gas and were "ready to fire." It quoted the source as saying new U.S. intelligence data showed the chemicals were "not just trace elements."
Recent polls suggest that Americans don't care overly much whether such weapons are found, but their discovery is absolutely key to US standing in the world community after the war's over. Or, more precisely, if they are not discovered, then the US's main rationale for the invasion has been undercut.
While it's unlikely that countries opposed to the invasion will change their tune retroactively, if the worst-case accusations against Saddam are borne out, it will still have a major impact on international relations.