No big deal to answer this one.... If it' s an outside recruiting firm, and they' ve called you for a job that pays in the range of $50k/yr, and you' re making $60k, why waste anyone' s time? Unless you' re willing to take a pay cut, and then you tell them that.

If. on the other hand, you are making far less than you feel the job warrants, and you' re asked your current salary--either by the employer or an external recruiter--you can say: "My current salary is $XX,XXX per year, and my expected salary for this job is negotiable within the range of $YY,XXX to $ZZ,XXX." If they question why you expect a higher range than what you' re now making, it is up to you to make your case. You need to know what you will accept to switch jobs, what you honestly feel the position is worth to them with you in it (based on how well you meet its requirements), and have some rough idea of what similar jobs in your area pay. Despite some  opinions to the contrary, I think you need to have some inkling of what an accurate "market rate" is in your area. But you do not get that from salary survey sites like salary.com. But you do not use area market value as a basis for your salary expectations or during negotiations with an employer. But I think when talking with recruiting agencies, it' s perfectly acceptable, IMHO, to say that based on talking to others in your field and on what other employers are paying for similar positions to candidates with your experience and skills, your expectations are such & such. My husband was underpaid in his last position, so we thought, and most of the recruiters he talked to gave him feedback that he was indeed underpaid. So it was good, as Chet says, to get that feedback; thus, he knew what to look for and how much to negotiate if needed.