If you are interested to find out what your attachment style is there are several ways to go about this. The "gold standard" has always been to have the Adult Attachment Interview administered by a trained researcher. This is the instrument used in research to identify attachment patterns in adults. However finding a therapist who is trained to administer this instrument can be difficult! Another adult attachment test that has been developed is the Adult Attachment Projective. However, this also needs to be done by a trained professional and not all cities (and certainly most rural areas) have anyone who has this type of training.
In an effort to find a method for people to determine their adult attachment classification I have tried various self-administered tests. The one that I have found to be most useful is on the website of psychologist Diane Poole Heller. Her self-administered test can be done online and gives you results immediately. Rather than being fully categorical (meaning you can only have one classification), her test creates a pie chart showing you what percent of your responses line up with a particular style. This is much more in keeping with what I see as a clinician-- that in some situations a person will look anxious-ambivalent, but in other situations they may look more anxious-avoidant for example. I think her approach makes sense clinically and is also easy for a lay person to understand.
For a really great understanding of how your attachment style impacts your romantic relationships I strongly recommend listening to Dr. Stan Tatkin's MP3 download, "Your Brain On Love". It explains in plain English how your childhood attachment style influences your romantic relationships in adulthood.
Remember, even those of us who came into adulthood with insecure attachment styles can learn new ways of being. With the help of a good therapist we can learn to re-pattern our ways of relating to mimic those of secure functioning couples. This can bring increased harmony, enjoyment, intimacy and stability to our relationships. Thanks to neuroplasticity we all have a chance at the benefits of a secure attachment to that special person.