Here is Kucinich's 10 Point Plan to Bring Our Troops Home from Iraq. You will note that he has explicitly laid out exactly what I said it was "obvious" that he meant. Immediate withdrawal means "immediate negotiations with the UN to effect an immediate transfer of control to the UN with US funding commitments".
It isn't that there shouldn't be troops there. There should be UN troops there. They should be funded with US dollars because i t is our responsibility to rebuild and keep the country secure but we should outsource the rebuilding to the international community rather than to our own military industrial complex. From all indications, the world will be happy to step up to the plate to help out. Peace keeping forces are supposed to be neutral. An aggressive invasion force operating outside the rule of international law is not neutral.