The snake is a difficult dream symbol because it is so widely interpreted among various cultures. Interpretations run the gamut from blood-curdling fear to wisdom and peace. These options are determined by literary history and folklore from different cultures, as well as personal experience.
In waking life, it is not uncommon to be afraid of snakes. For some people, this fear is disruptive and pathological, even to the point that a photo of a snake represents an oppressive threat. For these people, snake dreams are almost universally bad. If the dream includes someone who handles snakes, whoever tames the object of the fear is likely a source of wisdom and control in the dreamer's world, and may be a representation of some aspect of themselves or someone else they know.
Among Asian and Native American cultures, the snake is a wisdom symbol. The idea of wisdom comes from the snake's ability to shed its skin and renew itself. If one dreams of snakes from this perspective, it is a dream of renewal, problem-solving, and good tidings in general.
In Judeo-Christian cultures, the snake is a symbol of temptation or spiritual opposition against reaching one's goals. This concept is derived from Bible when Satan tempts Adam and Eve in the Garden of Eden in the form of a snake. Sometimes, a snake dreamt in this context will remind you of a particular person in your waking life with whom you have a competitive relationship.
Finally, Freud and classical psychotherapy have also thrown interpretations into this "pit." The contention is that the snake is a type of phallus. The snake often embodies fear about intercourse and an aversion to it.
Coming up with an insightful interpretation for your dream snake could be tricky. What emotions are prevalent regarding the snake: fear, respect, or opposition?
What is your attitude about snakes in waking life: neutral, fearful, or friendly?
Did the snake appear when you were alone or were others with you when the snake entered the dream scene? What are your feelings about those others?
Answering these questions should lead towards a productive interpretation of the snake dream.