Organic Consumer’s Assoc. has an article about Ethanol based fuel.

Some excerpts:

Corn ethanol does reduce atmosphere-warming carbon emissions, but environmental organizations such as the Sierra Club say it actually is worse than gasoline in making smog.

Fly on down to Rio for a look at the world’s leader in sugar-cane ethanol. Brazil’s widely consumed ethanol is almost eight times more fossil energy efficient to produce than the US corn-based stuff. Its ethanol manufacturing is powered not by fossil fuels, but by cane-stalk residue.

Brazil makes ethanol from sugar-cane, which is almost eight times more energy efficient to produce than the US corn-based fuel. Crops with high cellulose or sugar content that can be easily grown in the U.S., such as sugar beets, hemp or switch grass, make much more efficient fuels.