Making ethanol from corn is a good thing if you want to offset fossil fuels from overseas. On the greenhouse gas side of things, it is not clear if corn, as grown today, is a good thing. We just don't know yet, but it appears to be a mildly good thing.
The people who are saying ethanol is bad are just plain wrong.
Converting to fuel ethanol will not require a big change in the economy. We are already ethanol ready. If ethanol were available on the supply side, the demand is there.