Bush Administration has shown its plan concerning the post-war government of Iraq. It will be headed by an an American citizen of "high stature" (ie. politician) and will not recognize any Iraqi provisional govt. as mentioned by expatriate groups.
There will be a certain criteria used to determine which Iraqi govt. officials will be kept, and which will be replaced. The US plans to keep a large number. These will must first be "de-Baathified" just as Nazi leadership has "de-Nazified."
There are also humanitarian aid efforts to immediately follow invading US troops. The goal being to make the Iraqis feel "immediately" better off with Americans in their midst.
There is as of yet, no price tag or predicted length of stay. http://www.washingtonpost.com/wp-dyn/articles/A37949-2003Feb20.html