Do you use a harness on your dog?  

I don't like harnesses on dogs they look so uncomfortable. When I had my ferrets I had to put little harnesses on them and they worked well. I'm just not a fan of harnesses. I go for the leash more. I'm getting a new yorkie next week and definitely won't put a harness on her. But I think this is a personal decision for the owner.

I tried to find harnesses for my dogs but I wasn't able to get harnesses to fit them. I thought it would help keep their leashes from sliding under their legs. I'd try the harness to see if it works and if you don't like it just go buy a collar. They aren't very expensive.

Actually there are three basic methods to use. The collar, the chest harness, and now they have come up with a head harness whch is quite similar to a horse halter. The head harness is used for the much bigger dog as it offers more control by using pressure points, etc.
You haven't mentioned your dog's weight but either the collar or the chest harness would be fine. Since the dog is small you probably will not have trouble controling it, so use either. You can use the harness if a small child is walking the dog as this prevents jerking and pulling on the neck. The harness removes the pressure from the neck to the total chest area eliminating neck problems. The harness will not help prevent pulling though so as your dog grows you may want to change to a collar.
The regular collar reduces pulling by putting pressure on the dogs neck when they pull. For some dog this helps and some it doesn't. There are various collars to purchase to reduce pulling although again, these are for bigger dogs.
Some people feel the chest harness is the most humane as it gives the dog the least restraint.

I have two dogs. With my cocker spaniel I use a collar and leash. She's bigger and its comfortable for her. With my Chihuahua I use a chest harness and leash. The vet actually reccomended it because using a regular collar and leash can damage her windpipe if she pulls at all. Apparently, according to the vet, many small dogs come in with windpipe injuries due to using a collar. She walks much better on the harness too.

Hi there. Yes when we take our dog out walking we have a chain connected to her collar, because she is not a very social dog, and cant be trusted to follow along without taking off across the road or after another animal...

I use a harness on my 3 dogs, as I find it easier to walk them that way. I also think it more comfortable for the dog.
Babies used to have harness's years ago, when they were just up and walking, (don't think they called them harness's though).

I find I have more control over the dog's with a harness.