The ultimate green commute is as close as your own two feet:

By walking to work, one day or more per week you'll:
Save money:
Reduce Stress and Improve Health: Regular physical activity, such as walking to work, helps reduce the risk of coronary heart disease, colon cancer, high blood pressure and diabetes. It also helps in controlling weight, relieving symptoms of depression, and developing healthy bones, muscles and joints. 
Create a Better World: Walking benefits the environment and helps create more livable communities.