To track commitments, the Bush administration keeps a color-coded chart of coalition members: red for countries withdrawing, yellow for nations considering a pullout and green for countries staying.
Seriously, though, as the violence continues and kidnappings have become an effective tool of the insurgency, it looks like it might be just the US and the Brits (with perhaps a few Eastern European nations) with boots on the ground come January. And we don't have enough troops there now to establish security.