It was only a matter of time before someone turned services like these into a Google Maps mashup. And this time it was the Googlers (Googlistas?) themselves who did it.
Introducing Google Transit.
Google Transit not only allows you to search the best route between two given locations, but you can specify time requirements as well ("best route at 8AM," or "I gotta be there by 6PM!") and it will even estimate the total fare (and give you a cost comparison for public transport vs. what it would cost you to drive yourself!)
At the moment, Google Transit only includes information for the city of Portland, Oregon, but that's just a demonstration and proof of concept; I'm morally certain that within a few months, you'll be able to find your way around any major American city you find yourself in.
Say that you need to go from 100 NW Couch St in Portland, Oregon to Hillsboro, Oregon and get there by 8PM. What route should you take, when do you need to leave and how much will it cost you?
Simple... just enter "100 nw couch st, portland to hillsboro, oregon by 8pm" into Google Transit et voila:
It'll take you a little over an hour and cost you $1.80
(vs. over $8 if you drove yourself.) You're welcome.
Need directions for Dallas's light rail system (the hotel room I'm blogging from this morning overlooks the St. Paul's stop on the Red Line), or figure out which bus to catch in Baltimore? It's all gonna be on Google Transit soon, I'd wager.
Google Transit (beta, currently has data for Portland, Oregon only)