You can't get more mainstream, old media than Fortune Magazine.
Fortune's April 2, 2007 issue, currently on the newsstand, is their first "green" issue.
Thanks to the Greenbiz.com Greenbuzz newsletter for the heads up.
Copyright 2006 - 2010 Anne Libby Management Consulting LLC, unless otherwise noted. (I'm a big user of images from flickr, including the header image, which from a photo called Stained by r.s.m.b. sees, used under Creative Commons license.)