Should I contact the hiring manager after an interview? I know she is a very busy person and the position I interviewed for has not been filled. However, I have not heard anything in reference to the position. After the interview, I followed up with a "thank you" email. I don't won't to send countless emails and begin to annoy her, but I would like to know if I am still being considered for the position.

Depends on what they said with respect to how soon the you expect to make a decision. I typically tell applicants I interview that I hope to reach a decision within two weeks, and feel free to contact me if you haven't heard back. In your case if there was no mention of how soon they expect to reach a decision I would call the hiring manager after about two weeks to see what the status is. Use the phone as opposed to email.