NoCatAuth: Authentication for Wireless Networks provides some useful food for thought regarding security and authentication in community wireless networks:

"To provide responsible wireless access, we need to securely identify users when they connect, and then only allocate resources that the node owner is willing to contribute. The built-in security features of 802.11b are designed to create a private network full of trusted clients; they aren't well suited to managing public-access networks. Fortunately, with the proper application of open source software, a secure and easy-to-use security framework can be created."

the article comes from an upcoming book from the upcoming oreilly tome, Building Wireless Community Networks :

"Building Wireless Community Networks offers a compelling case for building wireless networks on a local level: They are inexpensive, and they can be implemented and managed by the community using them, whether it's a school, a neighborhood, or a small business. This book also provides all the necessary information for planning a network, getting the necessary components, and understanding protocols that you need to design and implement your network."

relatedly 802.11b Networking News links to several articles that underscore the potential for cell/wifi convergence , driven presumably by the desire of carriers and infrastructure providers to capitalize on wifi "hotspots" :

"Mobile operators should certainly be worried. The combination of no licence fees - because they operate in the unlicenced 2.4 ghz band - relatively cheap and easy installation, a wide and growing potential customer base and high-speed connectivity - offering data rates of up to 11 mbps to wireless-enabled laptops or handhelds within 50 metres of any access point - means that these wireless hotspots will spread ever faster across the world."

nokia is listening .:

"Helsinki Finland-based Nokia stepped up their efforts to enter the home networking market with the announcement today of an agreement with KPN to provide them with Nokia Home Gateway products. These products are based on the IEEE 802.11b standard and enable data transfer at 11 Mbps."

look for phones and gateways soon that facillitate hopping onto "hotspots" with the associated billing and service provisioning for carriers.