Interestingly, Wi-Fi's reputed failings aren't discouraging Sprint. Krueck disclosed that his company is working on a consumer-level phone, which internally is called the Combophone, that can handle both voice over Wi-Fi and cellular calls.

"When you enter your home, there will be a special wireless [Wi-Fi] router that would pair with the Combophone," Krueck said. "Once you leave the house again, you'd use the [cellular] network for your calls."

Krueck stressed, however, that Sprint's Combophone won't work over Wi-Fi outside the home -- the planned Sprint router is necessary to make the VOIP part of the system work, and that router will be available only for in-home installation. He said he expects Sprint's Combophone to launch in the first half of next year.

While use of Wi-Fi for VOIP has its detractors, more robust and far-reaching mobile wireless technologies also are emerging. The best known of these technologies is mobile WiMax. Fixed WiMax is already a fully ratified standard, and the mobile version could be approved as soon as the end of this year.

In addition, IPWireless' UMTS TDD and Qualcomm's FLASH-OFDM are already mobile and available. All three of these technologies create wide-area IP-based networks and usually operate in licensed portions of spectrum, which makes them less prone than Wi-Fi to problems such as interference.