When asked about salary requirements, try the following approach:
"That's a great question that I will be able to answer later in the interview process once I know more about the position and its challenges, I should be able to accurately answer your question. Still, I have done research on www.salary.com, so I'd be looking for a position within the $k-$k base salary range. Clearly, you will want to be confident that I'm the right person for this position, as well, before discussing salary and benefit information with me...am I correct in assuming that?"
Excerpt from Salary.com