Google has begun offering live transit information in Google Maps. That means you can fire up the Google Maps web site in your desktop web browser to see where the bus you’re waiting for is actually at. But the service is also available in Google Maps for Mobile. It works in the Google Maps Android app as well as the mobile web site for the service as long as you have a supported mobile web browser.
Right now live transit updates are only available in 6 cities: Boston, Portland, San Diego, San Francisco, Madrid, and Turin. That’s because Google has to partner with transit agencies to actually get this data. Hopefully the service will expand to include additional cities soon.
I live in Philadelphia where the Southeast Pennsylvania Transit Authority recently rolled out a service called TransitView which shows the locations of SEPTA buses and trolleys equipped with GPS. The service is also available on smartphones, but it would be even more convenient if the data were included in Google Maps.