The Google trip planner asks people to enter their preferred itinerary, such as location of departure and arrival, as well as dates and time of travel. The site then gleans all available information on public transportation schedules to produce a trip planner.
The trip planner provides estimated walking time to catch the nearest form of transportation on the desired route, which transit line to catch and estimated traveling time. The trip planner also provides the estimated cost for using public transportation.
Sadly only available for residents of Portland, Oregon at this time.