Don't believe the hype. Most ethanol today is made from corn, which is highly inefficient to convert. Oil is used to produce the fertilizer, harvest the corn, ferment it, distill it, etc.
"Adding up the energy costs of corn production and its conversion into ethanol, 131,000 BTUs are needed to make one gallon of ethanol. One gallon of ethanol has an energy value of only 77,000 BTUS. Thus, 70 percent more energy is required to produce ethanol than the energy that actually is in it."
http://healthandenergy.com/ethanol.htm
The only reason its on the market is because of massive government subsidies. If more oil is used to make the ethanol than we save by using it, how does this help the environment or reduce our dependence on foreign oil? Only in some sort of bizarro world does this make sense.
Edit: Found this on another website;
"Corn-based ethanol is extraordinarily inefficient to produce - it takes 3 gallons of petrol or biofuel to make 4 gallons of corn ethanol"
http://theseep.wordpress.com/2007/03/12/biofuels-boom-raises-tough-questions-ap-report/