UPDATE: eBay plans an IPO to spin off Skype as a public company.

Skype has begun testing a connection to corporate Voice Over Internet Protocol systems, which is something that enterprises have been asking for years.

Although Skype and corporate VOIP systems share the goal of avoiding phone company toll charges by routing voice and video calls over Internet-based data networks, they don't automatically work together. Corporate IP PBX phone systems typically employ a standard called the Session Initiation Protocol (SIP) to set up calls, whereas Skype uses a proprietary protocol. Now the two worlds will be linked with a new product, Skype For SIP for Business Users, which is entering beta testing.

The system allows corporate users to use their desk phones to make outgoing calls that can be routed over Skype's network at its low rates (about 2 cents per minute for most locations around the world). Skype users will also be able to make free calls to participating companies, and the cost to the company will be a fraction of the cost of a traditional toll-free number, according to Skype.

Why didn't this happen sooner? Although Skype has sometimes cited technical barriers to integration, another reason was that until now Skype didn't feel ready to tackle the business market, said Stefan Oberg, Director of Skype for Business.

"All the way from the start, we said we were targeting the mass market consumer in our product development and the communication," he said, and the business built itself around consumers who were willing to set up their accounts via self service and download and install it on their own. "Business tends to want someone to come in and educate employees, install a video conference room, provide training, and be there if something goes wrong. We haven't been able to provide that support until now."

Even though Skype will probably provide most of that corporate support through consulting partners, the company need to carve out the time to create those partnership programs, he said.

Despite the lack of explicit support for business use, Oberg said about 35 percent of Skype users surveyed said they use the service for business purposes. For example, a traveling executive can use his laptop and a headset to make Skype calls to colleagues who run Skype on their PCs back at the office. The difference is that with the Skype for SIP integration in place, he could also place calls to colleagues who don't use Skype, instead making the phone on their desk ring.

About 10 companies are already testing the system, Oberg said.