Here is a great documentary covering the water-powered car, alcohol-powered cars, hydrogen fuel cells, as well as the murder and supression of scientists/inventors who refuse to sell out. Youtube has censored Part 1 which you can view here. The rest of the documentary can be viewed here.
Here is the 80s news story about water car inventor Stan Meyer and his murder:
Here is a 2008 Reuters news story about Japanese venture company Genepax and their water powered car which runs at 50 miles/hr using only 1 liter of water for every hour of use: