You should always ask intelligent, well thought-out questions during or before the conclusion of the interview. Recruiters will almost certainly interpret this as a sign that you are genuinely interested in the job.
Here are some examples of questions you could ask during an interview:
Would you describe a typical work day and my responsibilities?
How would I be trained or introduced to the job?
What are the department’s goals for the year?
Who are the people I would be working with and what do they do?
Can someone in this job be promoted? If so, to what position?
If hired, would I report directly to you, or to someone else?
If you were to offer me this job, where could I expect to be in five years?
Could you give me a brief tour of your office?
In what major markets does this organization compete?
If hired, would I be filling a newly created position, or replacing someone?
How had your company / organization changed in the last several years?
What do you see as the future for this industry looking ahead?
What do you like most about working here?
Does your company plan to move into any new markets or offer new services?
When do you expect to make a final decision on hiring for this position?
This is only a partial list, and you should give some serious thought to developing other questions that you might want to present during the interview. Hint: Researching the employer on the Web can help you think of many ideas for additional questions.
Never ask questions about:
Only discuss these topics if the interviewer brings them up first. You want to assure the employer that you are more concerned with ways you can be a valuable employee than in your immediate financial gain. These questions are best left to the second, or "follow-up," interview.