Google took its wireless ambitions to the next step on Friday, submitting a proposal for providing wireless internet access throughout San Francisco. Few details of the plan were provided, but the city had asked for ideas and comments on how to provide access to everyone in the city either free of charge or at low cost.

Google's was one of 24 proposals received, Mayor Gavin Newsom said at a news conference yesterday. If the rest of the decision-making process goes as smoothly as possible, such a service might go live within five or six months, Newsom said.

Google is already dabbling in wireless projects. In April, it began sponsoring a hotspot in San Francisco's Union Square, and last month a page appeared on Google's website offering download instructions for Google Secure Access, which it says "allows you to establish a more secure connection while using Google WiFi." The company has so far declined to elaborate on its Wi-Fi plans and could not be reached for comment yesterday.

San Francisco is exploring ways to provide a ubiquitous high-speed wireless service in order to create an attractive city for innovative people and businesses, as well as helping economically disadvantaged residents get online, Newsom said. Last month it sought comments from the public as well as information from potential builders or operators of a service.

Google would provide both the network and the fundamental service for free, although certain aspects of the service might carry a charge, according to Newsom, who said he hasn't yet examined the proposals in detail.

Google most likely would find partners to actually build and operate a municipal wireless network, said Esme Vos, founder of the website MuniWireless.com and a researcher of municipal wireless projects. What Google would bring into the equation is money, she said. Google could build a system delivering ads to web users in specific locations, which could be determined through information from the access points. Background data about a user's characteristics and interests could target those ads even more precisely, she added.

Advertisers would pay Google a premium to deliver highly focused ads to those users, Vos believes, and the builder and operator of the network would get a piece of that revenue just for providing the transport of data packets.

Providing the service for free is the perfect way to draw in users for advertisers to reach, she said. "The more people that are on this network, the more valuable it is for everybody, especially for Google, and especially for the network operator," Vos said.