An article in Fortune this week that’s getting a lot of attention details BT’s plans to embrace IP communications in a big way, starting soon in Cardiff, Wales. According to the article BT is a few months away from shutting down its existing circuit-switched network in Cardiff and replacing it with a pure IP-based network. Besides the improved bandwidth and telephony features residents can expect with this upgrade, BT is touting the flexibility of the IP platform and how it will enable a whole new host of homegrown applications and services.

But what’s really cool about what will happen in Cardiff - and eventually the rest of the U.K. - is that BT is creating an open, standards-based platform for which anyone can develop new applications. In other words, the phone has the potential to become more like the Internet with its proliferation of cool new Web sites, tools and services.

“This whole thing is based on openness and transparency,” says Paul Reynolds, chief executive of BT’s wholesale operations. “We want to allow experimentation by application developers.”

This is no small thing. Right now, for example, most of the mildly interesting stuff consumers can do with their phones - call waiting, caller ID, call forwarding - is programmed right into the big computers that route calls around the network. That makes it virtually impossible for some entrepreneur in a garage or some teenager tinkering at his computer to develop a new phone service.

Actions speak louder than words, but if BT really does encourage this kind of experimentation on an open and transparent telecom network, they are leagues ahead of most other telcos, especially here in the U.S.