Clearwire Corp., a wireless Internet service provider started by Craig McCaw, has begun selling an access card for laptop computers, taking on Verizon Communications Inc. and T-Mobile USA Inc.

The service, which uses Clearwire's high-speed network, will cost $59.99 a month, plus a $6.99 monthly rental fee for the card, Clearwire Chief Strategy Officer Scott Richardson said. It's targeted at consumers and small businesses, he said.

Clearwire, based in Kirkland, Wash., operates in 44 U.S. markets, including O'ahu and parts of Maui. The company is expanding its service beyond customers' homes to lure new subscribers and spur sales growth. In three to four years, the mobile product may generate at least as much revenue as the home service, Richardson said.

The laptop service is faster than connections offered by companies such as Verizon and Wi-Fi hot spots run by T-Mobile, Richardson said. It won't appeal to large businesses because Clearwire doesn't offer coverage in big cities such as New York and Chicago, he said.

Clearwire, which had 299,000 subscribers at the end of last quarter, will sell a package of home Internet access and the laptop card for $94.99 a month. The first three months will cost $79 as part of a promotion.

The company's shares have dropped 14 percent in the past two weeks on concern that construction of its network will be delayed because negotiations with Sprint Nextel Corp. are taking longer than expected. The companies plan to build a network using a technology called WiMax that runs more than five times faster than today's standard. They aim to reach 100 million people with the service by the end of 2008.