Esther Dyson shows a screen shot of the new Google map screen (may not yet be available where you are) for New York City with a "Take Public Transit" option. Esther is reaching this screen from within the Google headquarters. Commenters indicate that they are not able to access the same screen as Esther shows.
Her screen shows a route from La Guardia Airport to the Meetup Headquarters where she has office space. She credits Tom Sly of Google for the new green and indicates that real-time transit information is coming soon to a computer near you.