Joel Makower at Two Steps Forward provides a summary of various attempts by research firms to segment the green consumer marketplace. At last count, there are apparently at least six different segmentation models, including a recent one from a WPP's Landor Associates, Penn, Schoen & Berland (PSB) Associates and Cohn & Wolfe (C&W) which sees the green world divided into active greens, muted greens, green motivated, green hypocrites, and green ignorants.
Not because WPP is the parent of the company for which I work, but I like this one the best. (I haven't read the study, but my suspicion is most of us fall into the green hypocrites category.) Seems to me the same consumer categories could also work for segmenting corporate environmental behaviour.