I will give you a slightly different viewpoint than the others so far. I have a 30 month old. She still takes a bottle of milk before her nap and before her bed. I am not stressing about it - it sooths her and I think there's really no big deal about it. Our pediatrician has said it's fine. /the nap bottle has about an ounce of expressed milk (yes I am still pumping) mixed with cow's milk.
However, during the day, with meals etc, she drinks out of a regular cup (not a sippy). She LOVES her regular cup - we were given some plastic ones - Scooby do, snowflakes, etc - little plastic tumblers with designs and she likes them. We did start with the Nuby sippy cups that everyone recommends but really just use those in the car now. At the house we use the regular cups and she loves it. We do also use a different specific cup for each drink - water versus milk - I do think that helps them know what to expect.
Obviously it's up to you but if you aren't comfortable with cold turkey, tell her bottle are only for certain times (before nap or bed or whatever) and the rest of the time we drink out of regular cups. My daughter always wants to be like Mommy so if it's pitched as drinking out of a cup like Mommy's all the better.
good luck!