You might remember that back in June, mobile VoIP provider Rebtel (News - Alert) mentioned that it was kicking around the idea of an IPO to raise funds. According to industry observer Jim O’Neill, the company has rolled out the latest iteration of its Apple (News - Alert) iPhone app which lets users “move between connections on-the-go as call quality dictates.”

Version 2.0 lets users choose how they want to connect calls, O’Neill explains, “either via Wi-Fi, 3G or with local minutes.” It gets better, though: As he notes, users also can opt for the app to automatically select which service it uses, depending on network quality.

Tech journal Arctic Startup wrote that Rebtel “came out officially with a whole lot more than just free calls between iPhone (News - Alert) users,” as the company announced what Arctic considers “cool new technologies to their application as well as making the free calls platform independent.”

Specifically, Arctic noted, the Rebtel technology is KeepTalking, which lets users on a WiFi (News - Alert)/3G connection switch to a local call if the connection quality begins to deteriorate. Just “click on the KeepTalking button to transfer the call to a local number for better quality,” Arctic says.

It’s an important feature, since, as Rebtel officials realize, the market for telephony services is big. All together now: “How big is it?” It’s so big, it’s twice that of all TV operators and three times more than all Internet-related revenues.

 “Voice calls generated some $628 billion in revenue for operators last year, which is two-thirds of all revenue and accounts for half of all the profits for the companies,” Arctic noted for emphasis.

Rebtel officials add that the app detects if call quality degrades, and if that happens, it gives users the option of switching to a carrier voice network. And don’t worry about skyrocketing charges you can’t control -- as company officials say, “Smart System always chooses the cheapest option for the calls.”