Having just said that cats and dogs can get along, a word of warning: some dogs have a strange—and dangerous—reaction to very young kittens. In a word, they eat them. Sadly, this can occur even if the dog had been friendly with the mother cat.
Dogs and cats are both creatures of instinct, and even a dog comfortable with adult cats may look upon tiny kittens with their high-pitched mewing as (alas!) something to eat. Naturally the mother cat, if present, will fight the dog tooth and claw, but the dog is more likely to do its dirty work while the mother is absent. A word to the wise: if your cat just had kittens, try to keep them out of the way of dogs.