I personally was notified 9 days after my interview via e-mail. I don't know if that is common or not, however. At the interview, we asked when we should be expecting to hear from them, and they told us 2 months so I was quite suprise to hear that early. Perhaps others on here can give a better estimate.
some people dont hear for months, I heard back in 4 weeks. It really depends on when/if the adcomm can get together with both of your interviewers to discuss your app.
The committee meets every week and sends out final decisions about once a month. So the wait time can be variable, depending on whether the committee has discussed your application or not.