Bones

There is no war in Iraq, something like this is commonly refered to as an occupation. After a war is won, territories get occupied. The Netherlands were occupied during World War II. The (rather limited) opposition to that occupation was called The Resistance, often The Undergound allthough the Germans might have called it an insurgency. Look where it got them.
Germany got occupied after World War II. A chunk of it got a fairly democratic government, albeit no army right away, another chunk got a totalitarian boot in it's neck and became Democratic in nothing but name. This took a while to topple over but after Poland it did and the domino effect so dreaded in Asia finally came to pass in Europe, and so much for the better.
Allright, lets light the candles, shake up the bones, cast them on a sheet covered with astrological symbols and do some future prediction for dummies.
So, this occupation will come to an end. Even the USA doesn't have the stamina to persist in this insanity.
Some day the government will be deemed democratic, appropriate and satisfactory, allthough it will not be, not even by a long shot[1]. Apart from the three northern provinces, aka Kurdistan, where they seem to have a better grip.
Some day the Iraqi army will be deemed qualified enough, allthough it will not be, not even by a long shot. They don't even have an army. They have subdivisions in US Armed Forces infrastructure, backed by US artillery, armor, airsupport and guided by them spooky 'advisors' much like crawled all over indochina[2].
The USA will pull out, Cheerleader News Networks will dub this 'cut and run', BushCo will blame the Democrats, who will have won back the house and/or senate in 2006, and made it impossible for him to stay the course, thereby aiding the enemy.
The full blown civil war shortly thereafter will be a humanitarian disaster, ethnic cleansing all over the place, but not for the entire area formerly known as Iraq. Shia's and Sunni's will battle over Bagdad and southern provinces, climaxing over Basra but up in the north the Kurds will close their border and declare an independant state of Kurdistan. The Turks won't like it none but the people in control of this particular slab of real estate, soaking with oil, will have a lot of leverage. The problems between Kurdistan and Turkey will be problems for the European Union.
Problem solved.
Next stop: Teheran.

[1] The Iraqi Government Is Little More Than a Group of "Talking Heads"
[2] There Is No Iraqi Army
from "7 Facts You Might Not Know about the Iraq War"