I saw this image on Flickr (thankyou Mista Fitz) and thought it was a rather strong image of what many people think is wrong with biofuels at the moment. It may not tell the whole story in terms of the price of food. It's a pretty healthy-looking piece of corn, not a dried-up seed head from a drought-struck crop, and the greenery implies quite a lot of celluosic ethanol. If there were more cellulosic ethanol then the pressure on food prices might be quite a bit lower.