That's not really quite a deal considering that a vehicle (unless tuned strictly for ethanol) would experience a semi-hefty decrease in mpg.

It's sort of a catch-22, it's great for the environment emissions wise, but takes large amounts of resources to make. I haven't seen any exact numbers, but i'd say it's a pretty safe bet that after you factor in the energy consumption of the distillation process, the energy cost and detriment of fertilizer, tractors, and any other resource that still relies on an oil or gas based powerplant, that you're either marginally better off or equal to gasoline in the pollution sense. And really you don't benefit much unless you have an engine tuned to take advantage of the capability of ethanol, but if you do then you know exactly the crazy amounts of power to made even w/ an N/A application.

Bio-diesel on the other hand is a much better fuel to produce and use. However, I think it'll be a long way off before that becomes mainstream. Ppl have a skewed view on diesel b/c they equate excess black exhaust w/ pollution when in all actuality the emissions you cant see from a gas engine are insanely worse.