The US telecom regulator FCC has been looking into why Apple rejected an Internet telephony application from Google for inclusion in its iPhone application store. Responses from Google, Apple and AT&T, the exclusive U.S. iPhone carrier, are due today.

Along with Google Voice’s consumer fans, the outcome of the inquiry will be closely watched by other Internet telephone services such as eBay’s Skype. Apple approved a Skype app for iPhone but consumers can only make Skype calls when they are connected to a short-range wi-fi network and not via the AT&T cellular network.
The head of another U.S. Internet telephony provider Vonage weighed in on the topic in an interview this week. Vonage plans to offer its own mobile communications application later this year.

Marc Lefar previously served as chief marketing officer of Cingular, now AT&T Mobility, where he helped put together the mobile operator’s iPhone deal with Apple, before becoming Vonage Chief Executive last year. Taking his previous experience in the wireless industry into acccount, Lefar said it was unclear to him why the Google Voice application was rejected for iPhone.

“These apps we’re talking about, to me … seem to be reasonable to allow, relative to the range of things that have already been put into the app store,” he said.

“I think its very hard to defend a unique service and to distinguish some services in the communications space (from) others if all they do is use software to be able to provide that service,” he said.