Broward County, Flor., consider county-wide Wi-Fi: The Ft. Lauderdale-containing county, with a population of 1.8m, is considering building a network. This cautionary article in the Miami Herald talks to a variety of local and national folks about the failure to anticipate complexities and costs in building such network. There is no county-wide network I know of that has proceeded very far due to service provider and utility pole problems. Miami-Dade County, for instance, had issues with gaining mounting rights and had to install new poles of their own--without disturbing sea turtle nesting sites.
Note the appearance of Verizon-dominated USIAA's David McClure who states, inaccurately, "Cities ran out literally by the hundreds to spend millions on engineering studies." Cities typically spent tens of thousands to hundreds of thousands for proposals; in the vast majority of cases, the service provider paid for engineering studies before building. McClure often has interesting insights, but should be disclosing his group's entanglement, which is used to mask bias towards large telecom interests.
Rural New Hampshire and Vermont (isn't it all?) looks into large-scale wireless: Wireless LINC of NH and VT is a plan to bring Internet access to the beautiful hinterland. The first stage of the network is planned at 400 sq mi in 2008. Rural areas have challenges (where to mount, where to get electricity, trees), but also the benefit of a lack of density, and often high points that are already wired with aircraft warning lights, cell towers, or other communications gear. They'll be testing different technologies and approaches.
The ultimate network size would be 6,000 sq mi and be run on a wholesale basis. The focus is on dial-up only users, rather than on competing with existing broadband service available in larger towns and cities. The project is estimated at $12m. That seems laughably small for such a large network, but given the particular focus and density, that might not be off base. It's also unclear how much equipment end users might require. A point-to-multipoint system would make much more sense in this environment.
Palm Beach Jewish temple has Wi-Fi: Temple Emanu-El has free Wi-Fi and encourages people to come, eat lunch, and work as part of a tool to foster community. No word as to whether the network has a timer that shuts it off from sundown Friday to sundown Saturday.