February 4–11, 2012 Maine (caucus)
February 7, 2012 Colorado (caucus)
Minnesota (caucus)
Missouri (primary) – *See note below on Missouri
February 28, 2012 Arizona (primary)
Michigan (primary)"
'via Blog this'
Don't know about Maine, but seems pretty likely to me that Romney wins Nevada and Colorado (because of the Mormon vote) Minnesota (near Michigan, where his Dad was governor) Arizona (Mormon vote), and Michigan (see Minnesota).
Things can change, and I'm no expert, but I don't see any way at this point Mitt is not the Republican nominee.