E.N.
I weaned both of my babies off of the bottle right around their first birthdays and it was a piece of cake (no pun intended!:) They were taking 4 bottles a day at that point - one with each meal and one just before bed. My first baby actually refused the bottle completely, 2 weeks before his first birthday. So I never had to try to wean him, we just went straight to milk in sippy cups. But with my 2nd baby, I had a little plan: I replaced one at a time starting with the mealtime bottles. Instead of the formula in a bottle, I gave him milk in a sippy cup. And I waited at least 4 days between each "dropped" bottle before dropping the next one. The bedtime bottle was last. We always read a book to him while giving him that last bottle, so we just continued the same bedtime routine with no bottle and he never gave us any indication of missing it. I think we might have given him a sippy cup, but I can't remember now!
However you decide to make the transition, be prepared - my babies never drank as much from a sippy cup as they did from a bottle. It really concerned me with my first, but I think it was just the transition of getting used to the sippy cup. The intake did gradually increase. I just kept the sippy cup around constantly and offered it a lot in hopes of getting them to drink more. They must have been getting all of the liquid they needed - they never showed any signs of dehydration and they are still growing healthy and strong a couple/few years later.
Don't worry - I think the younger you wean him off of the bottle, the less traumatic it will be. It was no trouble at all with mine (though my first doesn't really count since he refused it himself). Good luck!