In this video Dr. Diane Poole Heller goes through the four attachment styles and gives examples of each. Our attachment style is set by the time we are three years old (give or take) and barring any effort to change it remains fairly constant throughout the lifespan, shaping all of our relationships.
Four Attachment Styles
This is a pretty basic introduction, but it's solid information (even though my own sense of these styles is a little different from hers). Dr. Heller is the founder of Somatic Attachment Training & Experience (SATe), a series of groundbreaking somatic adult attachment workshops for therapists.