From the National Corn Growers Association:

Q. You used to be an outspoken critic of ethanol. Do you believe now that it should be part of America’s energy future?

McCain: “I do, because, one, of its role in reducing dependence on foreign oil. And also when oil is $10 a barrel, it doesn’t make a lot of sense; when oil is $70 a barrel, it makes a lot more sense. I’m for all kinds of ethanol. I mean, corn-based is obviously the flavor of the month — and I’m all for it — but we also need sugarcane-based ethanol, such as what’s coming out of Brazil, and we need switchgrass biofuels. There should be a broad variety of sources of ethanol besides just corn. And by the way, I still do not support subsidies for ethanol; it’s doing just fine without them.”

[…]

(OutsideOnline.com, October 1, 2007)

[…]

“I don’t support any subsidies. But I am a strong supporter of ethanol because I don’t see any scenario where the price of oil is going to go back down again.” (Sioux City Journal, March 8, 2007)

[…]

“Ethanol does nothing to reduce fuel consumption, nothing to increase our energy independence, nothing to improve air quality.” (Fortune, October 31, 2006)

[…]

“I support ethanol and I think it is a vital, a vital alternative energy source not only because of our dependency on foreign oil but its greenhouse gas reduction effects, ” McCain said during an August speech in Grinnell, Iowa, (Associated Press, August 1, 2006)

http://www.ncga.com/vote2008/candidates/Republicans/mccain.asp

He was against it, before he was for, before he was against, before he was for it.

(I might have missed a flip-flop or two.)

MSM led you astray on that one.