did you specify on your resume package or cover letter your salary requirments? if so, then assume they will meet them. If not, it is reasonable to offer them now and ask if that is within the range they are expecting when you return the call to discuss the interview.
however, be aware that often the proposed salary for a position can be negotiable if they decide they really like you. I once gave up on a company after hearing the low salary range they anticipated, but they liked me well enough after the interview to make a very good offer in line with what I was expecting.