USC sophomore Neal Kolnik might be among thousands of cell phone users who change service providers later this month.

But he won’t have to switch phone numbers — and could save money on his phone bill, too.

Starting Nov. 24, wireless customers in the 100 largest U.S. cities — including Columbia and three other S.C. markets — will be allowed to keep their phone numbers if they switch carriers. Customers elsewhere will be able to do so by May 24, according to a recent decision by the Federal Communications Commission.

“It’s such a hassle to have to tell everybody — friends and family — what your new number is,” said Kolnik, 19, of Walhalla. “It’s a lot easier when you can keep the old number.”

For many people, wireless phones have become as important as traditional “landline” phones in the home or office. But the lack of wireless local number portability has kept many customers from switching providers, even when they were unhappy with service or costs.

“I’d say up to 40 percent of wireless customers will change providers in the next 12 months after Nov. 24,” said Patrick J. Comack, an analyst with Guzman & Co. investment bankers in Miami.

Comack, a national expert on telecommunications, also predicts a 20 percent drop in wireless rates immediately after that date.

The prospect of lower rates is good news to James H. “Red” Roberts, president of United Energy Distributors Inc., an alternative energy firm in Aiken.

Roberts said his company pays Alltel $750 to $800 monthly for its use of 16 wireless phones.

“We may or may not stay with Alltel, now that the price of service should start coming down,” Roberts said. “After all, competition drives the world.”

Roberts will have to wait past Nov. 24, since Aiken is not among the top tier of cities. In South Carolina, the rollout will first affect wireless customers in Columbia, the Charleston area, much of the urban Upstate and Charlotte’s southern suburbs.

The six major national mobile phone carriers have stepped up advertising campaigns to retain and attract customers.

“Wireless companies are waging very aggressive campaigns to hang on to their existing customers, while taking customers away from their competitors,” Comack said.

Cingular is offering significant discounts to customers who continue service contracts for two more years. AT&T is offering $50 credits and airline miles to those who renew their service.

“Everybody is offering big incentives,” said Tom Matthews, Carolinas regional spokesman for Sprint PCS. “We’re certainly expecting a lot of activity.”

Among those who plan to switch providers is Dave Holscher, general manager of the Charleston Area Convention Center. By January, Holscher said, he’ll be switching the center’s wireless service from Alltel to Sprint, and he won’t have to change any numbers.

“Twenty of our employees have cellular phones,” Holscher said. “So it’ll be a lot more convenient to keep the numbers as they are.”

Other cell phone users said they were unaware of the new options, but are glad to have them.

“And here I just switched from SunCom to Verizon,” said Kelly Payne, 33, of Irmo.

Payne, a USC graduate student and a teacher at Dutch Fork High School, said she had to adjust to a new cell number because of her switch.

“It’s inconvenient because a lot of people still don’t know what my new number is,” she said.

USC freshman Layne Womick, a BellSouth wireless customer, also said she hadn’t heard about the pending changes.

“I like it, though,” said Womick, 18, of Marietta. “Once you give out your (cell phone) number to people, you don’t have to change it every time you get a new (cell) company.”

Wireless competitors are hammering out last-minute agreements to “port” each other’s numbers, as customers switch from one provider to another.

“It’s a challenge for everybody in the business,” said Tom Matthews, the Sprint regional spokesman. “It’s a new way of doing business.”