
Have a good look at this
link to begin with. At 4 your dog is a little old to be beginning a career as a stud dog and it is usually the bitch owners' who look for a dog not the other way round. Also, the bitch generally travels to the dog for mating not the other way round. If you are still interested, your dog's breeder, if they are reputable and knowledgeable would be the next step, or contact one of the Poodle Clubs for advise. And, of course, make sure your dog has had all the necessary health checks for the breed and that any prospective bitch has had the same. You really need to take advice or how will you know if the dog & bitch's lines are compatible?