Enneawhat? (Updated)

I was just reading a post over at Tony Jones' blog about the Enneagram profile of Mitt Romney.

I'm writing this as a confession/observation:

I'm a psychologist and I have no clue what an Enneagram might be.

So when I hear about stuff like this my default response is:

Someone has invented another way to make money on our narcissism.

Apologies to any Enneagram enthusiasts, but is there any psychometric literature on this?

UPDATE:
In the comments many of you have shared how you've found Enneagrams to be helpful. So apologies for any snark in my initial response. I confess to being a psychometrics snob. Professional hazard. As I've written about before, we are all snobs about something.

Incidentally, for what it's worth, I took an online test and came out as a Type 9, "The Peacemaker." (And I will not admit to that label affecting my narcissism...).