I don't think anyone will ever announce a victory in Baghdad. After a few weeks and a few hundred dead American soldiers, the CENTCOM briefings will gradually shift from "We are within 50 miles of Baghdad" to "Who needs Baghdad as long as we control the oil wells". Or maybe they will keep "pounding" the city with their night time fireworks to -- what do they call it? -- "degrade" the republican guard.
But one thing is for sure, namely that Saddam will remain in power just like last time, so it will be quite hard for the Bush-regime to declare victory. Maybe if Bush loses the elections his successor will be able to declare victory by achieving peace with Saddam.
On the other hand, how do we know that the whole war is not being filmed in Hollywood? In that case anything is possible.