It's an increasingly common scene: a telecommuter perched on a park bench, pecking away at a laptop. But a peek over her shoulder reveals a more startling sight: she's surfing the Web, outdoors and cable free.

Anywhere, anytime Internet access is gaining ground across the United States as wireless networks owned and run by their users spring up in more cities each month-25 at last count. Although companies like Texas-based Wayport and MobileStar have provided wireless access in places like hotels, airports and coffee shops, the new cooperatively run networks are, for the first time, allowing users to surf in outdoor public areas. These networks are set up by groups whose members lend out their Internet access by hooking high-speed digital subscriber line (DSL) or cable modem connections up to wireless base stations. These base stations transmit the bandwidth to any nearby computer-commonly a laptop or handheld-equipped with an antenna to receive the signal.

What began on the West Coast as "geek networks" set up mainly by computer professionals has taken a socially conscious turn in New York City. Urban researcher Anthony Townsend helped create NYCwireless, a volunteer organization, not just to provide wireless Internet access in New York's public spaces but also to bridge the digital divide, bringing broadband Internet access to poorer parts of the city. "A lot of the other groups are interested in building a network that's for themselves when they're outside the office or home," says Townsend. "We're trying to build a public service."

Townsend cofounded NYCwireless earlier this year after some Boston-area friends tried to set up a wireless network for a more mundane reason: they couldn't get high-speed Internet access in their neighborhoods. He found that the same was true in many areas of New York, especially low-income areas, where he asserts cable and telephone companies have not upgraded their infrastructure to bring in broadband access. While Verizon, for instance, says DSL service is available in every area of Manhattan, NYCwireless's mapping has shown the service's coverage is not nearly as extensive in Harlem as in other neighborhoods.