The company EV Rental Cars, in business since 1998, does just what it sounds like. They claim to be "the nation's only environmental car rental company", and although they don't appear to have any straight-up EV's for rent, they do have hybrids. Their rates appear comparable to normal rental agencies, and they have locations in almost all major California airports, as well as Pittsburgh, Phoenix, and Washington DC.

Now if only someplace like Enterprise Rent-a-car would merge with Flexcar, to create a car-share network a thousand times larger than the existing ones.