12 mo old... Bottle weaning...

With Hannah I weaned her from the bottle at 13 months.   Starting around 12 months I added 1 ounce of whole milk to her formula.   I would wait a couple of days and then add another ounce.  I continued this and the transition to whole milk didn't bother her (except for extreme diaper rash for a few days....something about the fat content in the milk causing it).
As far as weaning goes, I strongly suggest going by the farmers almanac's best days (www.farmersalmanac.com).   When I first tried to wean Hannah from breastfeeding she screamed and screamed.  I waited until it was the best days to wean (normally there are about 6 or 7 straight days) and weaned her with out much trouble.  The first night she fell asleep with out any trouble.  The next couple of nights she cried some ,but would finally give in and take the bottle.  So when I weaned her from the bottle I gave her a sippy cup to drink at night instead.  Same thing....a few nights of crying (really, more just whining than anything) and we were broke from the bottle.  She was only taking a bottle of the morning and the night though, so I think that helped some too.  Now I just have to get her sleeping through the night!
Good luck with the weaning!
Amy