Over at GigaOm, they're saying EarthLink will sell Wi-Fi-only VoIP phones in fourth quarter: For $10 to $25 per month, the voice plan will include calling and exclude data. They're testing phones right now for deployment, Katie Fehrenbacher writes, and expect the phones to work in transit--she reports their VP of VoIP says the testing shows current models work at up to 40 mph. Wi-Fi operators and aggregators have been settling on a much lower rate, such as the Boingo/Skype mash-up (still in beta after many moons and with hard-to-find, out-of-date copy) that offers unlimited service for $7.95 per month.
The biggest problem appears to be the cost of these phones--EarthLink will have to subsidize the phones for a while, and Fehrenbacher quotes VP Steve Howe saying, "this business will get really interesting when the phones get down to the $40 range." It's true. A new Linksys phone has all the right bells and whistles for using Wi-Fi on arbitrary networks, including a micro-browser for authentication and gateway page clicking, but it's nearly $400.