J.F.
According to La Leche League you should cut down 1 feeding every 6 weeks. Even with this though, my milk kind of never went away with my first child. I had literally stones on my breasts, and could not take any medication for this because I was pregnant with my second child, nothing else would help, I was in terrible pain, could not move, could not sleep. My ob-gyn told me to nurse her again. I did probably after 8-10 days, and then again after the similar time and that was it.
With my second child I simply borrowed a breast pump and was pumping after as many days as I could stand it - at first after 3 days, then after 5, a week, after 2 weeks and then that was it, my milk was finally gone. If you can - I can really recomend borrowing the breats pump (Medela double breast pump is great!!!). Important - you don't pump for long, you do not want to get the whole milk out, just some to ease the pain, or else you will keep stimultaing milk production. Good luck!!!