AT&T expects to sign up a million VoIP customers for their CallVantage service. Vantage was/is the name of a cigarette brand. Do you think they want to smoke the competition.
Given their pricing, they are less expensive for service than Vonage, and right now are, especially with the $19.99 a month for signing up now.
Their back end features seem very Webley like, and seem to make that service almost obsolete, as the call routing service is Webley's biggest plus.
AT&T though falls down on international rates compard to Vonage. My guess is they are using their own long lines, not IP for the international, so the IP service is really just a loss leader at this point for them.