Readings:
"The Big Five Factor Taxonomy: Dimensions of Personality in the Natural Language and in Questionnaires", by Oliver John, in "The Handbook of Personality", Pervin (Ed), Guilford, 1990.
Useful Links (from Sarah Waterson):
Big-5 Personality
Questionaire
Keirsey Questionaire (similar
to Myers-Briggs)
Enneagram