(Business 2.0) – Upstarts like Vonage and Skype are bringing voice-over-IP to the masses. But a bigger opportunity lurks in the $2 billion corporate phone market. Now, New York-based startup Popular Telephony is offering a new VOIP technology that dramatically cuts corporate phone costs while letting workers take their office phones anywhere. Its secret: peer-to-peer software called Peerio that's built right into handsets.

CEO Dmitry Goroshevsky founded the company three years ago to bring PC economics to the office telephone system. A traditional workplace setup requires a dedicated voice network and a private branch exchange, or PBX, to connect to the outside world and can cost upwards of $1 million. Cisco has been selling an IP PBX, which uses a data network for voice calls. But Popular Telephony eliminates pricey hardware altogether. Using a plain old PC, network administrators assign an extension to each phone. Peerio-enabled handsets—which will be sold through discount retailers and office supply stores—plug directly into a company's data network, where calls are routed through a gateway and then out. Since Peerio is based on Internet protocol, office workers can use their phones wherever there's a broadband connection. And though companies pay the usual rates to call conventional landline and cell-phone numbers, ringing up other Peerio and VOIP users won't cost a dime. A handful of licensees are manufacturing the phones, which Goroshevsky expects to hit U.S. shelves in late 2005. Now he's just waiting for corporate America to come calling. — OM MALIK