First of all you have a mentor. These are people that will help you, and more than likely they are at the place that you actually want to be. Perhaps they learned something that you need to know, and most likely that something is related to the business that you are in. These are individuals that will be able to help you greatly, but they do not receive payment for their assistance. Perhaps this is someone near you, or maybe your boss. Either way, they will provide you with the information that you need to further your career and get the job done efficiently.
Then you might have an individual that is able to help you out with something, but they might never have done it themselves. This is likely an individual who knows the subject matter inside and out, and gives you quite a bit of good advice. If they have not done it themselves however, and do not have all the practical experience, then they are a coach.
This brings us to the consultants. These are usually hired by individuals in CEO jobs or COO jobs. This is an instance where the company needs someone to call on, but a mentor just won't do. The consultant is paid, and paid quite well. They are usually brought in for some of the more complicated projects, usually long term projects though they can be short term. A consultant typically has worked in that very industry, and they have all the knowledge and experience. More than likely, they wanted more freedom, more pay, and had grown tired of the menial day to day work.
Next you have what is known as the virtual CEO. This is a person that has been where you are, either in the COO jobs or the CEO jobs. He or she has climbed to the top, and they more than likely got tired of it. That doesn't mean that they don't like being in on things though. That is why they stick around and give advice here and there when needed. Though an actual CEO might know what he or she is doing, there are going to be some choices. These choices can be particularly difficult, especially if the CEO has never made such choices before. The virtual CEO has likely made those choices, and therefore he or she will know the right decision, or if there is an alternative decision that the current CEO is just not seeing. Before you ask, yes, this is an actual position.
These are three major elements in any company, and discovering which of these you might fit into in the future can be difficult. All you need to do is look at your strengths and weaknesses, and if you want, you can begin to help those around you. This is your first stop on the road to becoming a great leader.