Japanese communications giant NTT DoCoMo just announced the coming release of the N900iL, a dual network 3G FOMA handset that will also operate on Wi-Fi networks.

However, this phone is clearly only designed for corporate users, preferably those who spend most of their time on campus. Why? Because the phones won't operate on public Wi-Fi networks (with the possible exception of an NTT network). A company needs to install a special server that will allow the phone user to switch between Wi-Fi calls and 3G calls, as well as browse the Internet. The features look pretty nifty, but anyone hoping to make a free call from a Starbucks is out of luck.

Now I am fully aware that mobile operators don't want to support devices that will cannibalize their voice business. Operators lives and die by "minutes of use" - the more minutes a subscriber uses, the more revenue for the operator. And yet minutes of use is such a short-sighted way to view a subscriber.

Consider wired VoIP. AT&T has embraced VoIP knowing full well that it will eat away at its long-distance business. AT&T wisely figures that if anyone is going to cannablize AT&T's business, it might as well be AT&T. I recently signed up to AT&T's CallVantage service and have been very pleased so far. The interesting thing in my mind is that now that long distance is unlimited as part of my plan, I find my minutes of use are a great deal higher than when I paid by the minute. We are quickly headed toward a flat-rate communications world whether mobile operators like it or not.

I'm not surprised to see mobile carriers resist supporting VoIP over Wi-Fi devices. In the US, however, I'm quite confident that even though most operators will resist supporting VoIP, one bold operator will push ahead and leave the rest behind. My prediction is that T-Mobile will be the first carrier to support VoIP (with limitations) followed by Verizon Wireless and Nextel

As for NTT DoCoMo. This new phone will make a great walkie talkie for corporate campuses, but will ultimately prove too limiting to users who actually go on a business trip or two. Motorola and Nokia will also be releasing phones that support Wi-Fi - perhaps they will find an operator willing to take more than a baby step.