We all know the iPhone has Wi-Fi. The new HTC Wing, launched by T-Mobile last week, also has it. RIM CEO Jim Balsillie said in a speech that we'll see Wi-Fi on a BlackBerry device by year's end. Will this new crop of devices convince U.S. carriers to offer fixed-mobile convergence services?One company, T-Mobile, is already planning to launch a nationwide FMC service sometime this summer. Though details remain skimpy, the basics are that users of special Wi-Fi and cellular converged handsets will be able to make calls from either type of wireless network and roam seamlessly between the two. The service is rumored to cost $20 per month. For T-Mobile, which doesn't have a high-speed 3G wireless network in the United States yet, this tactic makes sense. With its thousands of Wi-Fi hotspots dotting the country, it can provide faster data services to smartphone users.

R. Scott Raynovich over at Light Reading reported last week on Balsillie's comments about BlackBerry and FMC:

If you throw WiFi in our products...that's imminent...and you have a service that does the handoff, it's something that can be interesting in the latter half of this year. Most of the carriers are supportive of FMC. Seventy-five percent of calls to the PBX go to voicemail, so if you can send those calls to a mobile phone, you could [double] the number of calls.

FMC and enterprise devices like the BlackBerry would seem a match made in heaven. Even a simple call-forwarding service such as the one Balsillie described above would be a boon for network operators. More and more, both the enterprise and consumers are going to demand multiradio functionality. As more smartphones start to ship with Wi-Fi on board, there's no reason not to look seriously at FMC as well. So, what's the holdup? The other network operators are not saying.

With only one national FMC service announced, it's not terribly difficult to guess which network operator will probably have the first W-Fi-enabled BlackBerry. AT&T and others have undertaken FMC trials, but none has announced any plans to support it just yet. Until they do, T-Mobile will be leading the way.