Via National Review, the early exit polls from Michigan have it Romney 35 - McCain 29 - Huckabee 15. I've heard the same thing. NR is also citing local news reports that McCain has already left Michigan for South Carolina. That leaves Romney as the only candidate still in state -- presumably, at the Southfield Embassy Suites where his campaign is staging their primary night rally.
Of course, early exits had Obama winning New Hampshire, too, so make of this what you will.