Using its billboards across downtown New York City, CBS is creating a Wi-Fi hotspot that will give nearly 20 city blocks free wireless Internet access.

The service, called the "CBS Mobile Zone," will extend 20 city blocks from Times Square to Central Park South, and 6th to 8th avenues when it is fully complete. Portions of the network are already up and running.

Local businesses will also be invited to join the network through the placing of routers inside their businesses to extend coverage. These devices will be provided at no cost, the company said.

The initiative is part of a broader trial underway from the MTA and NYC Transit to test the viability of a Wi-Fi network in the city. Access will be subsidized by ads that appear during access to the network.

"This is another example of how the assets of CBS Outdoor are enhanced by new technologies," CBS Outdoor chairman and CEO Wally Kelly said. "This offering will allow us to evaluate the prospect of applying Wi-Fi capabilities across our Outdoor properties globally."

A front page will greet users with localized content including nearby business and entertainment listings, as well as news, weather and sports information. Citi and Salesgenie.com have signed on initially to advertise through the network.

Wiring the billboards also has another side benefit: when near the signage, interactive advertising opportunities could be delivered to the user. CBS said it planned to even individualize the content down to the particular billboard through which the consumer was accessing the network.