Whoever answers the phones in your organisation can tell you, their time is usually spent answering the same questions over and over again.
These are the questions customers and potential customers want to know the answer to before they deal with you. Post them on a WWW page and you will have removed another barrier to doing business with you and freed up some time for the phone operator.
Answering the most frequently asked questions is one of the most important things to include in your website as this can save you both time and money every single day.