The proliferation of search-engine listings and Internet Yellow Pages has led to an increase in scam artists who solicit advertising for nonexistent online business directories.

Unscrupulous promoters commonly start with a telemarketing pitch on the benefits of Internet marketing and offer a "free" 30-day trial, according to the Federal Trade Commission. The scammers then bill the company - sometimes using the familiar "Walking Fingers" logo and the words "Yellow Pages" on the invoice - whether or not the services were provided.

"These operations rely on the fact that small businesses, in particular, may not have rigorous ordering, accounting and bookkeeping procedures that larger businesses have put in place," says Jodie Bernstein, director of the FTC's Bureau of Consumer Protection.

The FTC urges rental companies that receive suspicious phone pitches for Internet services to file a complaint at its Web site (www.ftc.gov).