American Council for an Energy-Efficient Economy: Provides green car ratings, a green car shopping guide and green driving tips. www.greenercars.org
Cars.com: Compares green cars by category and size, price, make, mileage and year.
Green cars: Discusses several decisions that go with buying a green car, such as budget, size and features.
U.S. Environmental Protection Agency: Provides three search methods that compare different green cars in different locales.