Final Interview Follow Up Call?

About 2 months ago I applied to a small company. A month or so ago I finally got a phone interview. That led to a in-person interview, which led to technical essment, which then led to another interview with a CTO. All of the interviews seemed to go well. The HR manager even told me that they have been contacting my references and all of them so far loved me. Great huh? Well after the last interview they CTO told me that they would contact me within a week or two. And it's been a little over a week. Should I follow up with the interviewer? If so what should I ask? I have been very good about sending thank you letters after each and every interview thus far. I just want to know where I stand. Should I do it or wait until 2 week period is up?