In the Biblical sense there is a difference, although I have seen heated debates on this question even among Christians. Most ancient languages have two words for these "entities". In the Hungarian Bible translations usually the same word is used for both as in the time of the first Hungarian Bible translation there was no Hungarian word for "spirit" - it was created on in the 18th century. This caused a lot of confusion. In Greek you have psyche and pneuma, in Hebrew you have nefesh and ruach - you can find a lot of discussion on the difference. Here I put very briefly my rudimentary idea about this. I do not believe that there are three substances: matter soul and spirit. My impression is that the soul is a kind of "interface" between spirit and matter (at least in a certain sense). Theologians will explain it more precisely. Nevertheless soul is the center of the conscious self where decisions are made (soul = life in the New Testament). There are several other aspects which I would comment - but I am not sure whether your question is intended in this direction.
