What's next for Iraq is really a matter of what can be hammered out in the form a status of forces agreement between the two countries. Remember, the UN mandate making the US presence legal is due to expire soon and the US needs an agreement that is acceptable to both parties. Though there is a draft of an agreement in place a lot of Iraqis are asking/demanding changes to it before it becomes finalized.

What the agreement ends up being will largely bind Obama to the agreement unless he starts negotiating with the Iraqis to amend once he is inaugurated.