It's little known that diesel vehicles are the perfect "flex fuel" vehicle. Unlike gasoline engines that need to have special features to enable them to burn different levels of an ethanol/gasoline mixture, diesel engines can burn any combination of petro-diesel and bio-diesel without modification. That means now!
So, while we wait for more flex-fuel vehicles to be manufactured and for higher levels of ethanol/gasoline fuel to be distributed, anyone with a diesel vehicle can use any level of biodiesel today. Just make sure it's from a reputable supplier. You can find locations at http://www.biodiesel.org/buyingbiodiesel/retailfuelingsites/
I like biodiesel because its renewable and reduces your carbon footprint by over 70%!