Key Terms in Jungian Theory:
 

Anima (feminine aspect):  the inner feminine part of the male personality or a man's image of a woman.

Animus (male aspect):  an inner masculine part of the female personality or a woman's image of a man.

Archetype: a  recurring image, character, narrative pattern, theme, or symbol that has been  present in literature from the beginning and that regularly re-appears."

Jung views archetypes as primal, ancient images/experience that human beings have inherited.

Collective Unconscious: "a set of primal memories common to the human race, existing below each person's conscious mind" (Jung)

Persona: the image that an individual presents to the world

Shadow:  darker, sometimes hidden (deliberately or unconsciously), elements of a person's psyche
 

Wikipedia offers a good basic overview of Carl Jung's theory:
http://en.wikipedia.org/wiki/Carl_Jung

My favorite aspect of Jungian theory is the concept of synchonicity:
http://en.wikipedia.org/wiki/Synchronicity

Several Jungian archetypes are defined and illustrated here:
http://en.wikipedia.org/wiki/Archetype