Fixed mobile convergence :-)

A T-mobile ja tem um projecto piloto no qual e possivel fazer roaming the WiFi para rede celular e vice-versa. Mais, o WiFi nao tem de ser da TMobile; serve qualquer WiFi. E pelos vistos nao functiona muito mal, apesar de nao ser facil passar do WiFi para celular por causa da perda muito rapida de sinal... Nada que nao se conheca das auto-estradas; eles la hao-de resolver o problema , deem-lhes tempo!
As experiencias de quem testou o servico Hotspot@Home no NY Times.
Para quem nao quiser ler o artigo todo, aqui ficam um sumariozinho que me chegou por email vindo da JiWire.com:

The holy grail for Wi-Fi/cellular phone convergence is being able to roam freely from hotspot to cell net, indoors or out, without dropping calls or needing a geek degree to operate your handset. We're not there yet, but you have to give props to T-Mobile for trying. In the first public offering of such a service, the company is covering the Seattle/Tacoma area, and hopes to go nationwide over the next year or so. For $20 plus a cell plan of at least $40 per month, T-Mobile's HotSpot@Home gives you unlimited U.S. Wi-Fi VoIP calling on open home and office networks, as well as at T-Mobile hotspots. For customers who do a lot of calling in Wi-Fi areas, it can be a great deal, as well as a way to replace a landline.

The good news is that early testers report excellent call quality -- much better than Skype -- and a roaming handoff system from cell to Wi-Fi that mostly works. The bad, according to Glenn Fleishman's New York Times review, is that calls drop frequently as you move from Wi-Fi to cellular, and that hotspot connections are unreliable. Another issue is battery life -- Wi-Fi radios drain handset batteries much faster than cellular. (Two handsets are currently supported, the Samsung SGH-T709 (pictured), and the Nokia 6136. Both are GPRS/EDGE smartphones.)

To be fair, Wi-Fi connection issues are largely out of T-Mobile's control -- the company must depend on the user's equipment, and bear the brunt of any in-home reception issues like dead spots. Reliability will surely improve as the company gains experience. However, one key handicap Fleishman points out is that you can't connect to hotspots that require a login or even just a click on a home page without paying another $20 for an unlimited data plan. At least a minimal amount of data usage should be bundled with the service for this purpose, along with a warning if you go over the limit.