In one of my classes, our discussion tends to get confused as to the meaning of an interest versus a value. My own understanding is very much influenced by the book Getting to Yes: from the point of view of negotiation one should disclose one's interests instead of insisting upon a position. For example, two boys might fight in a schoolyard over the possession of an orange. The one boy's interest is to eat the fruit, the other boy's interest is the use the skin in a science experiment. They have taken incompatible positions, though their interests are not so.
Extending this framework to include values I would offer the following. Values are the beliefs or assumptions one has about the world that informs one's actions. Interests are the values instantiated in a particular context for a particular agent. Positions are then the stances an agent takes in fulfilling its interests. The agent might be a person or a community; the values may be latent/hidden or in conflict with one another; the interests are dependent upon the context and the agents understanding of that context; and there maybe more than one position that satisfies one's interest, and this too can be confused and muddled.