Normally I wouldn't bother to make a new article for this, but a lot of people were interested in the original post, and someone (Justus Stewart) finally sent in a link to a truly impressive transit-mapping application: Bus Monster.
Bus Monster hacks Google Maps to display nearby bus stops, the routes of whatever buses you care to look up, and when you click on a bus-stop bubble it shows you when the next few buses will arrive at that stop. You can even have it set an alarm to warn you a chosen number of minutes before the bus is due to arrive at that stop.
The tool is just a hack by Chris Smoak, but its interface is head and shoulders above anything else I've seen, including the professionally-built proprietary systems. The only problem is that it doesn't do trip-planning yet, which is a bit of a show-stopper. Also, it's custom-built for Seattle's online bus info, it's not universally applicable. But he says he's working on trip-planning data access, and he's going to open-source the code so others can do it in other locations. If all transit agencies used a single open-standard XML for input/output of trip data, writing the code once would make it work everywhere.
(thanks, Justus!)
