What are some other viewpoints on spirits other then the traditional Christian ones?

We are all made up of body (the physical dies on death), mind (which governs all) and spirit (which is the eternal part of our existence...it does not die). When someone sees 'ghosts' it is usually the lower, uneducated and 'stuck' spirit that have not moved into the light. If your loved ones moved into the light, they can come back to communicate (which is really what you want to know about) through mediumship but would not stay around in a 'haunting' type of existence. There is a religion called Spiritualism that uses mediums in their services and therefore does some good development of the techniques.