Questions? Yes!

http://lifehacker.com/5935550/the-interview-question-that-is-always-asked-and-how-to-nail-it

Good article on how to answer what any employer should ask in an interview, whether it's a phone interview or face-to-face, an initial interview or a callback for the umpteenth time.

"Do you have any questions for us?"

You should always come prepared with something to ask. That you've got a few questions shows you're interested. What you ask (and how) is a way to communicate what your priorities are. Do not ask questions like "is the company car I'll be getting a Porsche?" or "how many days can I skip work without getting fired?" (Okay, those are pretty obvious things not to ask.)

Rather, think about what you've seen in the job listing, what you've heard from people, and what the employer seems to want--and ask how you can contribute. More details in the linked article.