Today Google gives Mountain View free wireless internet access -- an example for organizations considering investments in the WiFi arena according to Minnie Ingersoll, Product Manager for Google WiFi. Google does not plan on extending this service to other cities according to the New York Times.
Is this a viable alternative to traditional internet service providers? Not yet, judging by messages from people who have been testing the service. It doesn't work great indoors, and it looks like sending email is a chore unless you have a Gmail account.
Even though this shouldn't be a replacement for your existing ISP, it does promote mobility and now users have the option to stay "connected" wherever they are. Granted, some people try and get disconnected by going outdoors -- now they will have to completely leave the city (or just turn their laptop off).
Portable devices that support wireless internet connections suddenly become more useful because of initiatives like this -- imagine a handheld device with Google Talk integration. As the technology improves, cellular phones could one day be replaced by devices with access to WiFi networks.
For more information about the Google WiFi network in Mountain View, check out this article by Om Malik.