on September 19, a CNN/ORC poll was released for the Michigan presidential election. Results for registered voters are: President Obama 51%, Mitt Romney 41%, Jill Stein 2%, Virgil Goode 1%, Rocky Anderson 1%, someone else 2%, undecided 3%. Here are more details.
For likely voters, the results are: Obama 52%, Romney 44%, Stein 1%, Goode 1%, Anderson under 1%, someone else 1%, undecided 1%. The poll did not mention Gary Johnson because he is not on the Michigan ballot, although there is a possibility he still will be.
Rocky Anderson has chosen to have himself listed on ballots as Ross Anderson, yet his campaign generally refers to him as Rocky Anderson. Thanks to Andrew Straw for the link.