In Michigan, SurveyUSA has John McCain leading Barack Obama by 4 points. Hillary Clinton was not surveyed, except as part of an Obama-Clinton ticket (that ticket trailed McCain-Romney by 5 points, picking up support from Democrats but losing a fair amount of support from independents).
While Michigan cannot quite be described as a "must-win" for Obama, it's safe to say that unless he wins two out of the three big rust belt states -- Pennsylvania, Michigan and Ohio -- he will have a tough electoral row to hoe.
It is interesting to contemplate whether Obama is hurt in Michigan by the dispute over its primary. Our regression model thinks that Michigan ought to be a fairly decent state for Obama, favoring him by about 4 points. Perhaps noteworthy in the SurveyUSA poll was the relatively high number of undecideds (21 percent) among Democrats; Obama also lost 18 percent of Democrats to John McCain.