We check in with our sophisticated colleagues to the north at Mobitus, who have pursued voice over IP over wireless for average folks and businesspeople: Mobitus is tightly allied with FatPort, a veteran hotspot operator in Canada which builds hotspots and platforms. Mobitus focuses on mobile VoIP, which means that Wi-Fi has to be a component.

The service offering has a Vonage-like list of services without the unlimited use option. But what's interesting is how they've pursued the Wi-Fi angle in a way that Boingo is just starting to look into with Vonage.

In the Boingo/Vonage deal, callers have to be subscribers to both services. With Mobitus/FatPort, Mobitus users can employ FatPort hotspots without a FatPort subscription. They'll sell you a Zyxel VoWLAN phone preset to automatically log on to FatPort locations--as I've said before, authentication to for-fee hotspots is a key element in making VoWoHS (Voice over Wi-Fi over Hotspot?) work. The phone also works at open APs, including one's home network; or APs protected with WEP but not WPA at this time.

Mobitus is charging a small premium at this point. There's no setup or monthly charge, and you can pay from US$0.05 per minute on a pay-as-you-go option or as little as US$.03 with a 1,000 North American minute plan. This is in contrast to Vonage's unlimited US$25 offering for North America, but Mobitus believes it has enough added value to charge for all used minutes.

This offering could be a platform, too, with Mobitus looking to create a method for other hot-spot operators to provide this service over their own networks. I imagine a roaming VoIP solution could be popular as well.

VoIP's big selling point is cost, not ubiquity. VoIP replaces a wired phone line for now. To bridge the gap and make VoIP a roaming technology that competes with cell, service has to be available over a wide swath of where a user might travel. Could there be enough hotspots for someone to choose to roam with a Wi-Fi VoIP phone instead of a cell? Or could you supplement one with the other, carrying two phones (heaven forbid), allowing the VoIP phone to forward to the cell phone only when the VoIP phone isn't active? It makes our head spin.