About a year ago, almost as a joke, we speculated in Wired mag about how you could conceivably use WiFi and Voice over IP to build your own DIY cellphone service. We didn't think anyone would actually do it — cellphone service isn't that expensive, and it'd be hard to get anything close to full coverage using WiFi — but long-distance company IDT says they're doing just that and are making an end-run around the cell carriers and are creating their own low-cost Voice over WiFi mobile phone service. Vonage is supposed to have a WiFi phone out later this year, but IDT is taking a slightly different approach. They'll be giving away the WiFi phones, which cost about $100, for free, and charge $2 a month for service, with pre-paid minutes costing about 5 cents each (incoming minutes are free). They're aiming the service at people who might not be able to afford both regular cellphone service and landline, and are going to put WiFi access points in places like senior-citizen and affordable-housing complexes so that people could use the WiFi phone could double as their home phone. We're not saying this isn't gonna work, except that we're saying it isn't gonna work. We have a feeling that the only people who are going to want a WiFi phone, at least for the immediate future, are business travelers who want the convenience of being able to get their calls anywhere, including overseas. With pre-paid cellular plans so cheap, it's hard to see why anyone would settle for a bastardized cellphone service that didn't work in most places.