Phone companies are losing about 2% of their customers every quarter to mobile carriers and VoIP providers like Skype. Now another type of company is after those customers. Consider Jajah the un-Skype, because unlike that service or Vonage, its customers don't need a Net-connected phone or headset to use its VoIP service.

To use Jajah, you type the originating and terminating phone numbers into a text box on the vendor's Web site, click a button, and wait for your landline or mobile phone to ring. When you pick up, Jajah's own internal system has already dialed the other number. Voice calls actually travel on a fiber network connected to Jajah's servers, not over the Internet.

International call rates start at zero between registered users and 2.5 cents for unregistered users in the United States, Japan, and most of Europe. Everything's handled on a per-call basis, so no contract is required. "It's really the only way for people to benefit from Internet calling rates without buying hardware, without downloading software, without compromising their networks, without signing contracts," Jajah co-founder Roman Scharf says.

The service has several features tailored for businesses. Conference calls for up to 10 users start at 2.5 cents a user per minute, set up through the same Web interface as regular calls. There are options to make scheduled calls and to send one bill to an entire company, and management features such as restricting certain employees' usage. Jajah uses 512-bit encryption when calls go to any of its 200 Internet backbone-connected call-termination servers and automatically switches providers when quality slips. Jajah's on pace to surpass a million users by the end of the year, and Scharf hopes it will become everybody's "second phone company."