Air power.

Cheap, nearly free, wireless Internet is spreading across the globe.

What if the Internet was free, in the air and all around you, all the time?

That radical concept is threatening to become a reality. Chalk it up to a new form of radio transmission, called wireless fidelity, or Wi-Fi. It costs about US$70 to install and the technology can send broadband-speed Internet to laptops and handheld computers up to a hundred meters away.

Wi-Fi's sheer cheapness could solve the infamous "last mile problem" of connecting the world's cities to the oceans of fiber-optic capacity laid in the late '90s Internet boom. It also threatens all sorts of business models, from telephone carriers who thought they would be charging fat monthly fees for wireless Internet over cellular phones to telecom gear vendors that counted on wiring up offices and schools for decades to come.

Mexican billionaire Carlos Slim is in. At Sanborn's Cafes--in Sanborn's retail shops owned by Slim--access to Wi-Fi is up and running, free to customers. Similar no-charge rollouts have already taken place in first-class airport lounges and five-start hotel lobbies all over the globe. A second model, offered by cellular carriers, relies on monthly subscription fees but guarantees more access points. Slim's Telefonos de Mexico (Telmex) Prodigy Movil service charges about $19 a month and says it has Wi-Fi "hotspots" from Cancun to Los Cabos. Similarly priced services are offered in Brazil through mobile carrier Oi and free Internet provider iG. Meanwhile, Brasil Telecom, Brazil's Vivo and Chile's Telsur are also testing Wi-Fi.

But those monthly charges are likely to drop, and fast, from $30 a month now on average to $3 by 2008, according to a Pyramid Research Study of Wi-Fi industry participants. The technology is so cheap to install that just about anybody with broadband in their business or home can do it, no extra carrier subscription needed.

Prices for competing services, like high-speed data over cellular telephone networks, meanwhile, will drop only slightly over time as more users sign on. Pyramid predicts.

U.S. chipmaker Intel has launched a Wi-Fi chip for notebook computers called Centrino that, among other things, it says, extends battery life for mobile customers. "The lesson of the cell phone is that users want to be untethered from the wall. The real benefit of Wi-Fi technology is that you can be productive for more of the work day," says David Hite, Latin American director for Intel.

Betting big. For handheld computer maker Palm, the advent of cheap, nearly free wireless Internet is part of a big bet, on the future, too. The company's newest corporate line, called Tungsten, features a "Wi-Fi model. "In a few years, it's going to be mandatory. People are going to expect it," says Carlos De Vries, Latin America and the Caribbean director for Palm.

The end of the high-speed-data road for telecoms? Not hardly, say some of the regions biggest phone handset and gear makers.

"We don't see it as a competitor," says Cesar Castro, Nokias business development manager for Latin America. "We see it working together with [cellular] wireless." Specifically, users will be able to use Wi-Fi, say in an office setting, then leave the building for an "edge" platform, a kind of high-speed data cellular zone in urban cores and business centers.

Victor Agnellini, vice president of the sales mobility division in Latin America for Lucent. Technologies, dismisses the idea of free Internet. Lucent has tested mobile Wi-Fi spots, such as on buses and trains, and it is likely to become standard in office buildings, parks and cafes. But, he says, business users will always want guaranteed access. "If you are going to have a sustainable solution in time, somebody has to pay for it," Agnellini says.

GREG BROWN * MIAMI