iPhone/iPad and android have free and low cost applications to utilize. Find the one best addressing the needs in your city.
iPhone Apps - Free
Provides transit trip planning, door to door directions for biking, bus, walking, rail, etc.
Android Apps - Free
Ride Chicago: https://play.google.com/store/apps/details?id=com.dattanlabs.ridechicago
Provides live bus and train arrival times and maps.
There are many other free and low cost apps located on the CTA apps web page.
Link to CTA (See your city for other resources):