Much of the information about the home I find on google. If is it currently listed, you will also find many interior/exterior pictures. Even if is is not listed, you can still, google still have information on the address.
I have my own quote form questions I use when I am first asked to quote. On some of the larger houses I do (5000 sq ft+) I usually tell the client or agent, I will get back to them with a price in the hour. That gives me a chance to google it and review the information.
As Scott said, be friendly, casual and professional. This is when you are wearing your sales hat!