You're about to negotiate a salary with a prospective employer, but you have no idea what the going rate is. What do you do?

One strategy is to check pay-comparison Internet sites such as salary.com and salaryexpert.com. The Web sites show salary ranges for hundreds of job titles. For instance, one says pharmaceutical-sales reps make an average $49,000 a year. (Salary-search tools also appear on dozens of other Web sites, such as Monster.com and this one.)

The sites say they gather the information from surveys of corporate human-resources departments. In some cases, it's the same data employers use to set pay scales.

There are two levels of service. A quick salary search is free. Then, for a fee ($49.95 at salary.com, $39 at salaryexpert.com) applicants can have a personal salary report drafted up with in-depth data and charts that support a more carefully honed estimate. It takes around five minutes to fill out the information needed for the report, which includes your work history, education and skills.

With unemployment high, pay is a prickly subject. Still, job experts say it's never wrong to ask for a little bit more from a prospective new boss. "It's still appropriate to counteroffer," says Deleise Lindsay, managing consultant in Atlanta for DBM, a career counseling firm. She used to work as a hiring manager in the banking industry and says, "I always had a few thousand dollars to play with. If they didn't ask for it, it was left on the table."

Is it appropriate to bring these types of reports to a salary negotiation? John Dooney, a northern Virginia recruiter who sits on the opposite side of the table from applicants, says "it's how you communicate it." He says the information can be helpful in initiating a discussion of salary, but urges that applicants "not be confrontational."

While the information is generally considered reputable, other factors also determine salary. Ms. Lindsay calls the Web services "very good research tools to let the candidate know what their market value should be as a baseline." She cautions: "There is a huge variable right now -- the economy." A weak job market is undermining pay, says Lawrence Michel, president of the Economic Policy Institute, a Washington research group. Real wages, which take into account inflation, fell in 2002 and he expects the job market to stay depressed in 2003.

With corporate budget crises pinching wages, Ms. Lindsay suggests applicants propose noncash compensation to sweeten a hiring package. Things like flex time, working from home and increased vacation are all chips to bargain over.