Hi A.-
I know this is not what you want to hear but the simple answer is throw away the bottles! If you don't give him the bottle and only offer him a sippy cup he will eventually learn to drink from it. Start with the soft spouted sippy cups so they are similar to the bottle. Also if he is dependent upon a bottle before bed or naptime you could keep those bottles but go to a sippy cup the rest of the time. It won't be easy, but he will adjust if you are consistent and make the change. If you always give him the bottle he will continue to want it.
The other option is to skip the sippy cup altogether. Just go ahead and give him a "big boy cup" instead of the bottle. My son just turned 2 in November and was off of the bottle and on sippy cups for a little over a year. He is now using a regular plastic cup most of the time. We only use the sippy cup in the car or to go to the park, etc.
Good luck,
K.