Wi-Fi's Calling Might Include Phone Service; Skype, Vonage Will Try; It has been used just for wireless Internet access, but can be used for voice.(INTERNET & TECHNOLOGY)

Byline: REINHARDT KRAUSE

The next big thing for Wi-Fi could be making phone calls via the Internet.

At least, that's the aim of Internet calling upstarts led by Skype and Vonage.

They're developing Internet calling software that runs on laptops and handheld devices that have Wi-Fi connections. To make calls, people would plug headsets or earpieces into laptops or handhelds.

When, and even whether, Wi-Fi calling will take hold, however, remains unknown. Analysts caution that the reliability and voice quality of Wi-Fi phone services are still question marks.

And it's not clear what advantages Wi-Fi phone calls might offer consumers …