Earthlink Inc. and Google Inc. have submitted a joint proposal for building a citywide wireless network in San Francisco.The submission in response to the city’s “request for proposal” was handed in this week, the companies said in a joint statement. Earthlink and Google last year told the city separately that they were interested in building the project. The city wants to build a municipal network in order to give poorer residents an affordable option for getting online. Mayor Gavin Newsom launched the wireless broadband initiative last summer, hoping to provide free Internet access to city businesses and residents. For more click here.