I forgot to mention this, but the Google Lat Long Blog just posted about it and reminded me. Starting a few days ago, many of the transit icons (bus stops, etc) in Google Maps became clickable. Instead of just showing you where a bus stop is, you could click on it to get exact times.
Obviously, they don’t have this in place everywhere. They get the data “through a variety of means, including transit agencies, geo data companies, websites and maps” and they’ll undoubtedly be adding more locations over time.
The example they give is of Zurich, Switzerland. Check it out and click on some icons. This should be a very useful feature for people that often use public transportation, especially in an area that they’re unfamiliar with.