B.C.
Dear Joy, It will be hard at first to listen to him cry, but it usually only takes about 3 nights then it is done! From the books "Solving Your Child's Sleep Problems" and "Baby Wise" I followed their suggestions and boy does it work. Begin one night and let him cry for 5 minutes. Go in and just comfort him with a soft voice - do not pick him up - do not give him a bottle. Only stay in there for 1-2 minutes. Leave. Wait 10 minutes then repeat the process. While he continues to cry, add 5 minutes to each time you go in to reassure him. One time this process lasted about 1 hour.
The second night you do exactly the same, except you wait 10 minutes until you go in the first time. The third night, wait 15 before heading in the first time.
Usually after 3-4 nights he will learn to put himself back to sleep.
One of the things they say is that you may want to feed him more solid food at dinner so he is not as hungry in the middle of the night. Also, food/drink in middle of night keeps their body more awake and they tend to be more active, not less. They say he may not be getting good sleep after he drinks because it activates the digestive system.
Hope this helps... it's tough at first but worth it for both you and your child in the long run!
God Bless!