a howto:
make yer own lotsa info & stories:
biodiesel america.org a guy near me converted an old GM highway bus [6-71?] to run on it, and made the trip to the east coast of Canada and back spending NOTHING on fuel - stopped at all the mom&pop fast food places and asked for their old fryer oil - lotsa times they even gave'em free food for takin away stuff they'd otherwise have to pay to dispose of - he said their biggest expense the whole trip was beer!!
they also stopped at the Toronto Transit yard and had the thing checked on their dyno for emissions - very much cleaner than normal diesel [and pleasantly smells like french fries

]
Bill