G.D.
My daughter was drinking from a sippie cup at 5 months, at 12 months was drinking from a straw, and at 22 months, she mastered the cup without a straw, though will still drink from a sippie cup or straw. But, I know of a girl who at 3 1/2 still takes a bottle all day long, and won't drink out of anything else. So, I don't know if this will help, but here goes...
On Rachel Rhae (sp?) a few days ago, Leah Remini (Carry from The King of Queens) was the guest. She was having an issue with her 3 year old daughter wanting bah-bahs at night -- 6 to 8 of them!!! Leah admitted she wouldn't say no or deny her. She enlisted the help of a viewer, but didn't follow-through with the plan of just giving her the bottle without the nipple on it. Finally Leah's mom offered to take the little girl to Disneyland over a weekend (3-days, I think she said), but only one 1 condition - that she left the bah-bahs at home. When she got back from Disney, they bottles had been trashed and although she's asked for them occasionally, she doesn't get them.
One other trick you might try - cut a tiny bit off the tip of the bottle nipple - just a little at a time. When they don't have to suck to get anything out, and it becomes more like a straw, they might not care for it anymore. Good luck!