My ds was off bottles by 11 mths (still actually cant believe we managed to do it!!) But literally at 10.5 mths I was still holding his bottle, whilst he was sat on my lap and I feeding him so it was quite amazing. So one day I just refused to hold his bottle, and let his sit on my lap, next day I sat him next to me, and the next day I got a different coloured sippy cup from his water cup (but the same cup), and gave him that - he only took about 3-4oz, and we had lots of tears, so I helped him have a little bit more and praised lots, the next day he had a bit more and so on.... As much as I hated the crying, it wasnt for too long and I gave him lots of reassurance, and held his hand and such, and was just there for him as much as possible without giving in so to speak. I felt I needed to get him off the bottle, as I was due his baby sister 2 weeks after his 1st birthday, and was worried he would get upset or try to 'steal' her milk which is why I started the process a bit earlier. Some people though dont take their baby off the bottle by 1 at all though. I would give it a try, if it is causing baby problems, then give them the bottle back and try again in a few more weeks. I think the thing to remember is that the 12 mth thing is a guideline, it doesnt have to be the exact time, so there is no need to completely rush through it.
Also my ds was only on 1 bottle a day from 9 mths, although he loved this bottle, I imagine it would be a lot harder if baby was still on a lot of bottles. I know my friends daughter (same age), is still on a night bottle, but managed to swop over her other 2 bottles to cups by doing it one at a time, and she is now working on the last bottle...
Good luck when the time comes