EcoKnight

An EcoTravel Miscellany

Car Sharing site

This is a great site, since it matches up potential car sharers, for free, not just for regular journeys, but also for one off trips. And you can use it even if you don't have a car yourself. Obviously the further from home you're travelling the less chance of good matches, but it's still an excellent resource.

http://www.liftshare.org/mycontrolpanel.asp