A few months ago, New York-based Web designer William Bright came up with a simple idea: Take digital images of subway maps, slice them into pieces and make them viewable on color iPod screens.

Two months and almost 100,000 downloads later, Bright has subway maps from 22 cities -- from Vancouver's SkyTrain to Berlin's S-Bahn to Washington's Metro -- available for download on his Web site, www.ipodsubwaymaps.com. The Metro's system map -- which is broken into several easier-to-read maps -- has become the third-most-popular download on the site, he said.

Bright's maps became so popular that they caught the attention of transit authorities in San Francisco and New York City, whose lawyers informed Bright that he was distributing their copyrighted map images without a license.

"Take the NYC subway map off your website and confirm to me by email that you will not do this again," read a terse letter from an attorney for that city's subway system, according to a posting on Bright's Web site. San Francisco officials also sent him a "cease and desist" letter for the iPod version of their subway map, he said.

In Washington, transit authorities gave Bright their blessing last week.

"I can't stress how cool that is," he said about Metro's response.

Bay Area Rapid Transit, which operates San Francisco's subway system, said that the map that Bright was using was out of date and that the agency is working to make its map, as well as its schedule, available in an iPod-friendly format within two weeks.

"We generally don't have a problem with people using our information if it's accurate and they ask first," said BART spokesman Jim Allison.

Efforts to reach New York's Metropolitan Transportation Authority were not successful yesterday.

Bright said that lawyers for New York's subway system said he could post the map if he paid $500 for a one-year license. He considered it and put the matter up for an unofficial vote on his site.

"I got a resounding no," he said. "Out of 188 feedback comments, 98 percent said no."

To get around such legal issues, Bright is designing from scratch his own map of the New York subway system, one that does not use the copyrighted images

It takes Bright about 40 minutes to put together a map from a high-resolution image; the largest of the maps takes up only a megabyte, a fraction of the size of a typical music file. Bright says he got the idea for from a posting he read on a productivity blog by a man who planned a road trip via Google Maps and then put the route maps onto his iPod.

Bright is currently figuring out whether he wants to add more maps; get approval for the other maps he's already posted; or make more of the maps he has already posted viewable on the Nano, Apple's tiny new iPod. He gets hundreds of e-mails a day from users and would-be users suggesting other transit systems to add.

Ideally, Bright says, other transit authorities will follow Washington's example.

Metro spokeswoman Lisa Farbstein said the agency is happy to let people access their maps in a way that's most convenient.

"We want people to know how to get from one place to another on our system," she said. "If someone wants to put a map on their iPod, that's fine."