Vonage Holdings Corp. is jumping on the municipal Wi-Fi bandwagon through a subsidiary that will resell broadband on EarthLink Inc.'s city wireless systems around the U.S.

Vonage Network Inc. will buy Internet access from EarthLink at wholesale and resell it under a Vonage-branded service in all the cities where EarthLink offers a municipal Wi-Fi network, Vonage said Monday. It did not say when the Vonage-branded service would go on sale or its price. EarthLink is pricing its Wi-Fi services around $20 per month.

EarthLink Wi-Fi is live in New Orleans, Philadelphia, and Anaheim and Milpitas, California. The company is also working on networks for other cities, and on Friday it reached an agreement with the City and County of San Francisco for a wireless project that still needs approval by the its Board of Supervisors.

The deal brings together two underdogs going up against increasingly large incumbent carriers.

EarthLink, which began as a dialup ISP (Internet service provider) delivering service over the phone companies' lines, is now betting heavily on municipal Wi-Fi as an alternative to the big carriers' broadband services. EarthLink also sells wired broadband, phone and satellite TV services and offers mobile phone service through Helio, a joint venture with SK Telecom Co. Ltd.

Vonage was an early provider of VOIP (voice over Internet Protocol) but now faces both incumbent phone companies and cable operators gradually moving toward that technology.

Subscribers to the Vonage service could use it for Internet access anywhere outdoors in the cities, and later this year Vonage plans to provide wireless modems and software tools to help them use the service at home in place of DSL (Digital Subscriber Line) or cable. Subscribers will also be able to use a future Vonage Wi-Fi phone to make calls on the networks.