Of course, like Darin, you can subscribe to green power, but for everybody else, ABG has an interesting post describing wondering about whether or not plug-in hybrids are any good, check it out:
http://www.autobloggreen.com/2008/02...air-pollution/
Here's the original article from USA Today:
http://www.usatoday.com/tech/product...ollution_N.htm