AT&T, in conjunction with some 10-15 incumbent telecom carriers — British Telecom, Deutsche Telecom and NTT among them — is plotting to launch a Skype competitor, according to a research report issued this morning by ThinkEquity analyst Anton Wahlman.

This is Wahlman’s theory for now, but his track record is full of theories that have eventually been proven right. For instance, he once issued a report that outlined 16 reasons why Cisco should buy Scientific Atlanta — which the networking giant went on to do, for $6.9 billion. For that reason alone, I put in a call to AT&T to get the lowdown, but all they would offer was the boilerplate phrase, “We can’t comment on this type of speculation.”

Anyway, back to the Skype competitor! Essentially what Wahlman is saying is that incumbents are going to offer a VoIP client that will work on the incumbent broadband/3G wireless pipe, and will use a backend platform that will allow folks to make free voice calls to anyone who’s logged into it.

Much the same way as Skype-to-Skype calls are free, incumbents could use their platform to keep calls from each other’s network free. The plan could help them avoid the termination charges and still make money when the calls go off the network to, say, a rival’s phone service or wireless network. “We believe that they will have to use a common client and common software platform in order to make this work,” Wahlman said.

Isn’t it too little, too late? Realistically speaking, there’s a slim chance of anyone catching up with Skype, which keeps adding subscribers and which, despite being mismanaged by its acquirer, has a momentum all its own. “Better late than never,” was Wahlman’s take.

Here are some key points about this yet-unnamed proposed Skype killer:

* To be launched in 2009.
* The concept will be extended to mobile phones eventually.
* The service would run on the carrier broadband connection, and also on top of the 3G/4G wireless broadband pipe.
* The service will be used as a lure for selling other services such as video.
* The incumbent consortium partners can brand this service any way they want.

Big shifts in the telecom landscape are forcing the carriers to think along these lines, Wahlman said in a chat earlier this morning. First, carriers are reluctantly facing up to the fact that voice has become a losing proposition. Thanks to competition from folks like Skype, voice is becoming essentially free. Second, they are losing fixed-line customers with an alarming rapidity.

As I have noted previously on several occasions, the carriers are in a race against time — these line losses basically make their plans to sell other services such as broadband and video impossible, thereby risking their future plans all together. The cost of winning back the customer who switches to, say, cable, VoIP, or a rival’s wireless service is just too high.

In the past, carriers have merely taken half-measures to address the voice-for-free problem. So this is radical new thinking: If voice is a losing business, why shouldn’t the carriers cannibalize it themselves, then sell other services, including video? As Wahlman noted, “Robust data connection is the most valuable service the carriers sell.”

Amen to that. I just find it hard to believe that the dinosaurs are finally getting jiggy with this new way of thinking.