The site for info is http://www.veggievan.com
They sell an excellent book that explains everything.I converted my VW golf with a rotary pump and ran on waste veg oil for over a year,until the suspension failed!
All the bugs are easy to work out over time.I biult my tank and all the plumbing from readily available materials.And yes the oil is free,a whole year of buying almost no diesel fuel.
The oil is disgusting to work with though.I left steel 20 litre barrels at my
participating restaurants,when they were full I heated the oil up with a coleman stove and puored it through a straining medium.Very messy and time consuming.
I would like to convert a school bus but it would take forever to fill the tank and once you are on the road getting to a restaurant at the exact time they empty the fryers is a long shot.In that case you run on regular fuel.