skadistic is correct. They are completely different.
Ethanol is the stuff you drink at a bar (normal people call it alcohol... ethanol is just the technical name). However, it is also an excellent fuel as fuels go. The drinkers might have problems knowing that they are burning it in the engine instead. I can't imagine it being cheap considering how much they charge at the bar for the stuff.
Diesel is a heavier petroleum fuel than gasoline. It gets pretty good gas mileage compared to gasoline. It is somewhat "dirtier" in sulfur, but "cleaner" in Carbon dioxide (though Europe forces refiners to remove most of the sulfur at the front end, so it's cleaner than the pre-2010 diesel grade in the US).
You can't drink gasoline or diesel. With additives they would want to add to ethanol to optimize it's use in car engines, I doubt you would want to drink the stuff out of the tank, so I guess they are similar in that respect. Don't drink the fuel.
Oh, if you really want to know the difference, use a search engine. The wikipedia probably has good descriptions too.