History is loaded with promises of quick wars and minimal bloodshed. While it is true that our troops are performing splendidly (as expected), US casualties have been -- thankfully -- almost unbelievably low, and that we may soon see a new government installed in Iraq (perhaps within a week), I would caution against predictions of a quick end to things.
I think we will see a long-term (i.e., permanent) US presence as "peacekeepers", which will make them targets for car bombs, suicide bombers, snipers, and any other sort of dirty tricks those ragheads can dream of. It will be like installing a lightning rod for terrorism.
There have been dicussions bandied about as to how long the US has to maintain a presence to see something like democracy installed. I think the most coherent answer to date has been, "As long as it takes."
My personal misgivings about the US role in all this stem from precisely that: I fear another expensive (both in terms of lives lost and money) expenditure of US resources with no end in sight.
It is nowhere near over.