Running Vehicles on Vegetable Oil?

the green giant asks: "There has been a lot of info on alternative energy powered vehicles lately, and this is good. However, most of us still drive the old-fashioned petroleum burning kind of cars. How hard will it be for us (the hackers) to take the lead in switching to innovative, replenishable energy sources? Well now it looks like there is a diesel/veggyoil HOWTO at The VeggyVan Website in the form of a book: From the Fryer to the Fuel Tank. I am ordering it now, so I haven't gotten the chance to read more than is on the website. Apparently you cannot merely pour vegetable oil in every diesel engine without problems, but you can (and there are instructions in the book) make your own biodiesel at home, and they claim to have gotten the price down to $.50 / gallon. Also, the book is supposed to contain instructions on how to modify any diesel engine to run off straight vegetable oil. I wonder how difficult this is to do. Has anyone read this book and care to comment on it?" Wow! I'm stoked that people are actually getting alternative fuel and energy sources into practical and everyday devices.

Fossil fuels will not last forever, we all know this, so it's great to see a breakthru like this one. While this probably won't yet take the world by storm, what do you think the automotive industry will look like in 10 years if technologies like this become commonplace in another 2-5 years?