With a Democrat controlled Congress, there has been talk of passing a Bill to require troop withdrawals, but the Whitehouse has also made it plain that GWB would veto any bill that required that.
So an Iraq war spending bill ($122 Billion - about $20 Billion of which is pork barrel) was just passed - and in it the Senators included a withdrawal deadline.
link
If the Bush administration wants the money then GWB cannot veto the bill. (or will he use "signing statements" to make changes on the fly?)
This is interesting, from a 3rd party point of view.