WaPo:

Romney asserted that the senator had changed his mind on President Bush’s tax cuts and repeatedly reversed himself on support for ethanol while seeking support in Iowa.
“Senator McCain was against the Bush tax cuts and now says he’s for the Bush tax cuts. He was against ethanol, then for ethanol, then against ethanol,” Romney told Fox News in an interview at a private airport in Fort Myers, after a small rally here. “I think Senator McCain is willing to say anything to try and get elected. He’s been looking for this job for a long, long time.”

The Romney campaign has been making this ethanol flip-flop charge for months. Based on the evidence I have seen, though, McCain has been consistent. He has been against ethanol subsidies but said that he has no problem with ethanol making it on the free market.