With Google Transit you can create your own transit trip, which comes complete with itineraries and maps. You can specify when you want to leave or arrive, compare the cost of various public transportation methods and see all the route possibilities. For instance in Pittsburgh, you can find out how to get from brunch at Pamela's to a 1pm matinee at the Waterfront- very cool!
The only downfall is it only includes 12 cities in the United States and Japan at the moment. But stay tuned for future city additions. All I can say is Google has been on quite the roll lately!