Yes, you should.  I have done this in the past with much success.  But you need to be prepared that they may turn the question around and ask you what you are looking for. 

When a potential employer calls to schedule an appointment, I usually ask them if they can give me a high level overview of the opportunity ( a lot of postings may not go into much detail).  At the end, when they ask if you are interested in coming in for an interview, I would ask "could I ask what the salary range of the position is?"  In most instances, they are going to ask you what you are looking for.  You can certainly position it that you will need to assess it once you learn more about the position and opportunity and that you are looking for a range to see if the position is in the ball park.  I often been given the range, and I have often been asked what the range is that I am looking for.  Either way, whether they give it or not, I thank them for understanding and that the only reason for asking is that I do not want to waste their time (or mine) if it is not a position that I would entertain.