Google has launched a limited test of a free wireless internet service called Google Wi-Fi in two locations close to its San Francisco headquarters.

The current test is limited to the heart of Silicon Valley, but the ramifications if the service was to go nationwide, or even worldwide would be huge for both Google, through advertising revenue and for the public with finally free Wi-Fi access.

The Google website has several references to Google Wi-Fi but provides few details. One page (

) refers to a product called "Google Secure Access" which is designed to "establish a more secure connection while using Google Wi-Fi".

Speculation about the announcement today was fuelled further last month following an article in Business 2.0 magazine, which argued that the company was considering building a US broadband network capable of targeting specific advertising via Google local to users based on the location of their Wi-Fi.