There are many places to look for your new puppy, including breeders, the RSPCA, shelters, or your local newspaper.
Try to get as many referrals as possible from reputable sources, such as vets, friends and breeders' associations, before contacting any specific breeder. Many breeders also have websites where you can read about the breeder's philosophy, view the breeding environment, see pictures of the puppies that are ready for adoption, etc.