Missed this one the other day. It seems that T-Mobile is now offering residential VoIP service for $10 a month with any cellular plan. This is not the same voice offering that T-Mobile launched last year through their WiFi service, but is a last mile service delivered over an existing internet connection. The offering (or what is currently known of it) has the potential to make T-Mobile an instant player in the residential VoIP marketplace.
The service is currently available in Dallas and Seattle, but unless the service quality is poor, you can expect to see this service expand quite rapidly given T-Mobile reach and marketing capabilities, not to mention the price.