-I dont mind that he barks when the doorbell rings but once I indicate that its ok I want him to stop.
- Not only does he bark but he growls at strangers which most people dont find cute

A 4 month old poodle growling? What does that tell you? It tells me that your dog has issues that are most likely genetic. At 4 months he is still a baby and should not growl at anyone. Growling is a defense mechanism and as we all know, defense, all defense comes from fear.

1. First teach your dog to speak. Every time he barks, say "Speak." Then when you want him to stop say "No!" (Don't scream it, this will make your dog think you're joining in). Repeat until he gets it. If this works, go to the next step.

2. Have a set-up for him. Get someone to come over and ring the doorbell. He should be better behaved. Repeat step 1 if it doesn't work.

As for the growling, is it from fear or aggression? That is, is he cornered by people, etc, and frightened by it, or is he trying to tell people to back off? This would help me more.

I have a chihuahua and she did the same thing. The best thing to do is to take your dog into busy areas(parks, around your block) to get him more used to people. This should help in time, but don't expect miracles. It is going to take patience. As far as your doorbell goes, a firm no, should give him the message. Repeatedly correcting him will eventually let him know that you do not like that behevior. I have also heard of some people getting cans or jars and putting change in them and shaking it when their dog does something wrong. Whatever you do just make sure it is consistent.

have you tried obedience school? he's clearly being protective of you, and you must be showing him signs that he's doing the right behaviour when new people visit. Make sure you're not patting him to comfort him when he barks at new comers. But I'd definitely be calling up a obedience school, your local vet may run one themselves and can help you probably quicker if they already know your dog. good luck

Watch the Dog Whisperer or see if there are tips here http://www.dogpsychologycenter.com/ . The guy's amazing.

I could describe some of the techniques, but it's best to see it in practice. Basically, he says you have to correct each time, but you also have to try to prevent needing the correction.