Tips for early preparation
I always advise that as soon as you are aware that there will be a new baby in the house, begin to prepare your family dog. Do not leave it until the new baby arrives. It is important that your dog associates the new baby with as few disruptions as possible.
It is essential to ensure that your dog has a basic understanding of good behaviour. The dog should be able to lie quietly for short periods, not jumping up, walking on a lead without pulling and coming when called are all essential. It is a good idea to teach your dog to walk gently next to the pram [stroller/carriage], but never tie the leash to the pram, and never when unattended.
The dog should also be accustomed to new items of furniture such as playpens, carry cots [cribs] and high chairs before baby arrives. If possible, get a tape recording of baby noises and play it in a tape recorder placed where the baby will normally be, so the dog becomes socialized to these sounds. Also teach the dog the difference between his/her toys and the baby's toys.
The importance of routine
Make sure that you develop a routine and stick to it when the baby arrives. It is important that the dog receives sufficient mental and physical stimulation. Try not to make a big deal with the dog about the arrival of the baby. Teach the dog how to approach the baby properly and gently. Allow the dog to make initial investigations and approaches.
Associate the baby's presence with positive things. Give the dog titbits and lavish praise for desired behaviour around the baby. Do not place the baby on the floor with the dog and never shout at or hit your dog for approaching the baby incorrectly. Gently show the dog what you wish him/her to do and offer a reward for responding.
Other things to remember
Due to the fact the a baby's immune system is not strong, ensure that your dog is healthy and is up to date with worming and vaccinations before baby arrives. And if your dog has any behavioural problems, make sure that you resolve these before baby arrives, or if you are in doubt about your dog's behaviour after your baby arrives, consult your vet, who can refer you to a local animal behaviour counselor.
NEVER leave any baby or child unattended with any dog.
Commitment, firmness, but kindness.