The Richwood Report

All people in sales want their customers to talk to them about their problems. The customers' problems are our key to getting in the door. For this reason, it's better to ask open-ended questions, that is, questions that can't be answered by yes or no alone. We want the customer to answer us with an explanation of what he is thinking. Justsell.com, a site we have recommended before for good sales-related material has a good list of thirty open-ended questions for sales professionals. The list is here. There's also some good advice for conversation with customers, or anyone else for that matter:

Ask the question and let the prospect or customer give you their answer.

No leading.
No prompting.
No interrupting.