Many of my clients have been asking whether they need a mentor or a coach. My answer is...BOTH!
There's a big difference between a mentor and a coach, but each one is invaluable to your growth as a leader and your success as a person. A mentor is an experienced leader in your field who can show you the ropes as well as offer you his wisdom. A coach won't try to tell you how to handle things--he'll ask you the right questions so that you'll discover the answers for yourself.
It's like being in a Broadway musical where the choreographer shows you the moves while the director asks you what you think about your character's motivation. Both roles are necessary for a successful production, and neither should intrude on the other's territory.
Make sure your mentor and coach are in place before your curtain comes up!