It's easy to find out if your new car has heated front seats, blue tooth capability or a plug for an iPod. But how does your choice stack up in terms of environmental performance and fuel efficiency? Not so east to figure out, right?

A new tool from YAHOO! and the nonprofit research and advocacy organization Environmental Defense will help.

"Consumers can think of the Yahoo! Green Rating as a yardstick that measures how well a given car cuts pollution," says John DeCicco, senior fellow for automotive strategies at Environmental Defense. "The Yahoo! Green Rating covers all of the major environmental impacts associated with a motor vehicle, from health-harming tailpipe pollution to greenhouse gases that cause global warming," he adds."