Proxim ships 802.11a technology: they claim as high as 100 Mbps using their own technology. However, according to the IEEE and other sources, the current U.S. regulations would limit the encoding system from sending more than 54 Mbps.
Fortune columnist weighs in on Wi-Fi costs: I disagree with Stewart here, as he's not considering the overall cost of doing business. Making long-distance or local calls using a modem for low-speed access can rack up several dollars a trip on its own. Having high-speed access means that a travelling employee isn't really disconnected from the network. Also, iPass and others are trying to build roaming accounts that a user can connect via to any available network, wireless, dial-up, or otherwise, that should consolidate costs.