Google Maps, Yahoo Maps, and even the old-school Mapquest are good at giving you driving directions. But they're pretty bad if you're walking, and they can't help you find your way via public transit. But a New York company, HopStop, can do this routing for you.
In addition to its Web site, which gives you detailed directions and maps for taking your trip on public transit, HopStop works via email and SMS, and you can also speak your start and end addresses into the system if you're in New York (it sends results to you via text message). The voice recognition worked perfectly for me, recognizing the Manhattan addresses I spoke on the first try. I did not try it from a noisy street, however.
There's another new and cool feature for New Yorkers only: The program will show panoramic views of the street scene at your destination subway stop, with an arrow overlaid showing which way to walk. If you've ever emerged from a subway in New York and wondered where the heck you are, you'll get what a useful feature this is.
The system will route you via foot, bus, and subway, and it covers towns and boroughs in the Boston, Chicago, New York, San Francisco, and Washington DC metro areas. Unfortunately, here in San Francisco it does not cover enough of the Bay Area; there's no way to get BART directions to or form Oakland, nor CalTrains routes to San Jose. Bay Areans should check out the 511.org trip planner instead.
HopStop CEO Chinedu Echeruo told me he plans to add more transit systems, and all the New York-only features, to all the metro areas the system covers. He also wants to extend the system so it can route people across transit jurisdictions, for example, from Boston to Washington DC.
I'm in favor of anything that makes it easier for people to use public transit, and I'd like to see walking and transit routing as an option on the major trip planners from Yahoo and Google. It'd be great if, when looking at driving directions, the cost and time of the trip on public transit could also be also displayed.