There were no precedents in early 2004 when Chaska, Minn., got fed up with the prices of local DSL and cable services and deployed a broadband wireless network for its citizens. The Minneapolis exurb of 20,000 dug $1 million out of its capital-improvement budget, built a Tropos Wi-Fi mesh and set itself up as a wireless ISP.

This ripple in the pond of municipal infrastructure advancements quickly became a tsunami. By the middle of last year, MuniWireless.com noted that it was "raining RFPs," and The Yankee Group analyst Lindsay Schroth estimates there are some 320 U.S. municipalities that have or are planning to cover themselves with broadband wireless networks.

Zero to 320 in less than two years is remarkable, given that local governments tend to lag rather than lead technology advances. However, U.S. cities large and small see the unmatched economy, mobility and application benefits of an unplugged last-mile solution, and are employing a variety of business models and architectures to get them.

The best approach depends on local circumstances, but Schroth sees some kind of public/private partnership as "an absolute must. Government doesn't have the capability to build, market and deliver innovative services. A better approach is for a service provider to build a wholesale network with a city as its anchor tenant," she says.

No service provider stepped up to the plate in Chaska, but larger cities such as Minneapolis and San Francisco have no dearth of suitors for their proposed municipal networks. Philadelphia struck an agreement last October for EarthLink to blanket the city with a broadband wireless infrastructure, deploying a Wi-Fi mesh for service delivery and using WiMAX backhaul.

The plan has competing wireless ISPs (WISP) joining city-owned Wireless Philadelphia as EarthLink tenants, with WP getting a percentage of the fees. Philadelphia also expects annual savings of about $2 million from replacing dial-up access and T-1 links used by field crews and remote facilities.