This Popular Mechanics article on alternative fuels has a lot of good information. It doesn’t completely incorporate the economic costs of, for example, having to transport the ethanol to the point of consumption separate from the gasoline. But it does provide a very thorough analysis of the different fuel technologies that are currently under development.
I also like the pragmatic, portfolio-focused perspective they take in their conclusion:
Today, many families have several cars–often more cars than they have drivers. So before we see our national fleet running on hydrogen, we believe that many households might have an electric or plug-in hybrid for short trips, an E85/electric hybrid sedan, SUV or minivan to squire the whole team, and a diesel pickup fueled by B30 or B50 to haul most anything else. All will reduce greenhouse gases and use renewable resources that come from inside our borders. By pursuing these multiple pathways, we can reduce our dependence on any single energy source–something we haven’t achieved with petroleum.
Hat tip to Glenn Reynolds for the link.