At 12 months, my little boy did 4 bottles per day. We just started replacing the bottles with a "Munchkin" flexible straw cup (available at W*lmart or B*biesRus) - filled with 3/4 formula and 1/4 whole milk. (At the advice of his Dr. we kept the evening time bottle but did the milk/formula mix) we did this, and kept increasing the milk, decreasing the formula until it was all whole milk and he never complained. He really likes the straw cups!
3 months later--we still have the evening bottle (advice of our pediatrician, since our son is adopted and has only been 'home' for 5 months, and recently had a medical procedure...the doc felt we should go slow phasing the evening bottle out since it's such a comfort thing--and with all the change/transition an adopted child goes through, and the recovery from the minor surgery, he felt it important to let him have this one thing for awhile).
We are about to phase out this evening bottle...Have heard one way is to start watering the milk down, until it is all water...then just replace the bottle with a straw/sippy cup of water-only before story time/bed time...or just immediately switch to straw cup of water and see how it goes...I think I'm going to go with the milk/water gradual plan...lol.
Good luck!