Skype certification means customers of these vendors can receive and send Skype calls via the certified gear. Inbound Skype calls are free, and businesses can buy Skype minutes to make outbound calls from phones attached to the certified call servers. Calls are carried between callers' local Skype points of presence to Skype POPs close to called parties, eliminating long-distance charges, via a service called Skype for SIP.

Skype for Asterisk is a separate program that supports the same features through open source Asterisk IP PBXs, plus it adds the ability to call Skype names from the PBX. Skype has also certified session border controllers from Acme Packet that facilitate the interoperability of IP PBXs with Skype's network.

Skype for Business is still in beta testing, a program for which 9,500 businesses signed up when it was announced in July, he says.

By receiving inbound Skype calls, businesses can reduce their 800-number costs because anyone with a Skype client or Skype phone can contact the business for free, Oberg says. Businesses can put a Skype calling button on their Web sites, so people with Skype who are browsing these sites click on the button and are connected to the business via a Skype call. He says a French insurance company receives 10% of its customer calls via the button on its Web site.

Hotels could use Skype for SIP for connecting potential customers visiting their Web sites to reservation agents. Once they make reservations, they could give friends and colleagues the Skype name for the hotel so they could acquire Skype clients and make free calls to the guests during their stays, Oberg says.