With Google Ride Finder, you can search for taxis, limousines and shuttles and make better decisions by seeing the exact location of vehicles in your area. Just enter a zip code, the name of a city or even a specific address. You will get a map showing the companies and where their vehicles are located.
I remember reading an article about a guy in Stockholm who made bank coming up with an über-cab company. Digital dispatch, lots of technical innovations that made sure your nice Volvo taxi was guaranteed at your door in 5 mins.
This is really a cool feature. Only thing that would improve it is if they used a Pacman graphic theme instead of a boring old map and pushpin.