While the Deathstar (you have seen the AT&T logo replacing Cingular’s, right?) fiddles on the iPhone and conventional telephony burns, T-Mobile’s made a very smart move by offering HotSpot @Home to its customers for unlimited voice calling via Wi-Fi connections at home, at the office, or on the road.

America’s Network thinks it could affect wireline phone companies, as 27%-41% of cellular minutes are calls from inside homes. In 1Q2007, AT&T lost 285,000 residential consumers, up from 251,000 lines lost in the same period of 2006. Tie those customers to T-Mobile, and that’s a big chunk of accounts.

The techiness of it all appeals to technophiles, a psychographic market slice that T-Mobile doesn’t reach well. Port your number to T-Mobile, and you’ve effectively got a one-number service, which telcos charge dearly for.

It also strikes at VoIP companies, for almost all of those charge more than T-Mobile’s $10/month Wi-Fi feature, though some do offer some international calling for free, which T-Mobile does not. And, stealing a page from their playbook, T-Mobile offers free wireless routers to sign-ups. Of course, you can still get one by telling FON you live next to a coffee house, but this is easier and easy sells.

It also helps T-Mobile compete against MetroPCS and LEAP Wireless, which offer unlimited calling for less than T-Mobile’s thousand-minute months cost.

Does Wi-Fi in a cell phone intrigue you? Join the discussion.