Get Mass-Transit Directions with Google Maps for Mobile
Version 2.2 provides transit directions for over 50 North American cities, from Ann Arbor, MI, to Tampa, FL. It also includes station information and schedules. And if your phone supports the My Location feature, GMM will automatically determine the starting point for your trip.
Peep the video up above to see the software in action. This version of GMM is available for BlackBerrys and most Java-enabled mobile phones. It's free.