I was talking to a telecom manager of a large U.S.-based multinational company recently who lamented the fact that worldwide data roaming charges are too steep and unpredictable to justify his business using the multimedia-centric iPhone as an enterprise device. Executives in his organization recently took some complimentary iPhone 3Gs overseas and returned to discover data-usage bills of $4,000 to $5,000 apiece. According to the telecom manager: "They had a cow!"

This particular telecom manager believes that the execs’ iPhone usage is an indicator of the future usage of all converged devices. As such, roaming charges represent an economic barrier to adoption of iPhones and other similar devices for multinational companies, he said.

“It seems kind of counter-productive to only be able to use the device fully in your origin country,” he wrote in a proposal to the iPhone’s sole U.S. carrier, AT&T, to request a better deal internationally. In the U.S., AT&T offers an iPhone 3G unlimited data usage plan for $45 a month, layered on top of a separately charged voice plan. The multinational finds that palatable, yet its policy is not to sanction devices for U.S. use only.

AT&T has created two global data plans that apply to about 65 countries, which can be further layered upon the voice and unlimited domestic data plans:

* $24.99/month for 20MB of data usage with overage rates of up to $.0195 per KB in some countries.

* $59.99/month for 50MB of data usage with overage rates of up to $.0195 per KB in some countries.

Bottom line: 100MB overage in many locations would cost nearly $2,000 — something the multinational I spoke to anticipates to be a likely occurrence and thus an adoption deal breaker.

There are plenty of issues surrounding roaming, as well as some emerging alternatives, which you can read about next time. Meanwhile, are international roaming concerns preventing you from deploying the iPhone or other mobile multimedia device because it’s hard for users to gauge how much data they are using? Please e-mail me, and let me know.

And so long as I’m asking for input, please consider taking the 5- to 10-minute Webtorials 2008 Wireless LAN State-of-the-Market survey. I conduct this annual survey in conjunction with Webtorials to determine how the WLAN market is evolving from a user-adoption point of view. If you are involved in WLANs for your company, please share your thoughts and experiences with us here.

Joanie Wexler is an independent networking technology writer/editor in Silicon Valley.