If you're interested in experimenting with a two wheel commute, let me remind you that in the Bay Area, and elsewhere around the country, Thursday, May 14 is Bike to Work Day.
If you can't ride the whole way you can try to bike part of your commute — because something is better than nothing for both you and the environment. In many other cities, Bike to Work Day is Friday — check the League of American Cyclists for listing of events by state. Regardless, be sure to check in with your local bike coalition since chances are high they will have watering stations set up for cyclists and many offer goody bags for pedaling commuters. Will you be biking to work soon?