T-Mobile will stop selling new @Home calling service; handset calling unaffected: T-Mobile introduced unlicensed mobile access (UMA) calling in 2007, where a dual-mode handset can place and receive calls over either a cellular network or Wi-Fi, and seamlessly continue calls as a customer travels.
This service works in homes and offices, and at associated hotspots. The service now costs $10 per month for residential plans with 1 to 4 phones, including unlimited domestic calls.
In mid-2008, T-Mobile extended that with updated routers that could also replace home landlines, allowing plug-in replacement of regular wired phones for an additional $10 per month. This service will no longer be sold, but existing customers can continue using it indefinitely.
It's not entirely surprising that T-Mobile would drop the landline replacement component. With an increasing number of households relying on cellular phones and no landline, the uptake rate was probably fine but had no growth curve--it only applied to people who wanted to retain the semblance of fixed home phone jacks. It makes more sense to focus on the pure celluar/Wi-Fi option.