They released a beta that works for a small list of cities. Years later there is still no released progress and in my opinion its killed a lot of competitors.
Its a great, though obvious idea. Local bus systems have the worst and least helpful web sites ever. A simpler global app would be invaluable. Except no one makes it because who would go out and start a mobile "When will my bus come to this stop" application with the probability of google transit launching at any moment? No one, and so a lot of innovation has been held back.
I get angry about that every time I sit at a bus stop. :)