Google (Nasdaq: GOOG) has entered into an agreement with a third party to extend its VOIP capability to the rest of the PSTN-connected world, Light Reading has learned.

This is a significant step for Google, as it extends the company's VOIP calling capability beyond the PC and into the circuit-switched telephone network.

Since last October, Google has been testing the interconnection services of VoIP Inc. (OTC: VOII.OB), a Florida-based holding company that is also a licensed CLEC, according to an SEC document filed by VoIP Inc. Monday.

From the filing: "On September 1, 2005, Registrant's VoiceOne Communications subsidiary entered into a Master Service Agreement with Google Inc. to supply Voice-over-Internet Protocol ('VOIP') services."

VoIP Inc.'s VoiceOne subsidiary company is in the business of providing domestic and international termination as well as E911 support.

Initially, Google intends to use the expanded VOIP service to support "click-to-call" functionality near its Web advertisements. (See Google VOIP Apps Stare Down Startups.)

"We are working with VoIP Inc. on a click-to-call advertising test, which we began late last year," confirms Google spokeswoman Eileen Rodriguez. (See Google Jabbers On and AOL/Google: VOIP Buddies .)

It's unclear whether Google would use VoIP Inc. services to connect its Google Talk IM client with the PSTN.

VoiceOne operates a nationwide MPLS network covering roughly 90 percent of the population and connects to the PSTN through a series of agreements with IXCs and other CLECs, a VoIP Inc. spokeswoman says.

The SEC filing further states "a series of purchase orders were issued for the interconnection of production of VOIP traffic, and Registrant has now effectuated a direct peering relationship with Google.”

VoIP, Inc. was obviously proud of its link to Google. The company's PR firm, HighTech Public Relations distributed copies of its 8-K filing SEC filing in a mass email to media members.

The filing goes on to point out that VoIP Inc. saw no profits from its Google trial in 2005, but it expects “material sales” of its services to commence in 2006.

VoIP Inc. has an interesting history, as Light Reading has previously reported. (See VoIP Inc: From Tea to Telecom.) The company was formed when a tea importer was sold to a Florida entrepreneur for $12,500 in 1998. The company soon went public under the name Millennia Tea Masters Inc., folded in two telecom-related startup companies, and later changed the umbrella company’s name to VoIP Inc.

The company’s VoIP Solutions subsidiary provides infrastructure development services and customer premises equipment, and its DTNet Technologies subsidiary (acquired in 2004) does distribution and fulfillment services for the company's own operations and for third-party broadband products.

— Mark Sullivan, Reporter, Light Reading