My first concern is whether your dog has all his shots. Parvo, distemper and rabies are all dangerous diseases that you expose your pet to every time you take him outdoors. Please get him his shots as soon as possible, then rabies will not be a concern.
Next, you must get control of your dog. Practice walking the dog on the leash and don't allow the dog to drag you. While I didn't see an article in the Pet Keepers library yet, I'd keep checking back to see if any new articles have been uploaded. In the meantime, there are a lot of free training videos online. I'd highly recommend watching them and implementing the trainers instructions. Here's one website: http://abrionline.org/videos.php where you can see techniques for handling your dog when he becomes agressive toward other dogs while on the leash.
I didn't see in your post, you do walk the dog on a leash, right? If you don't, please begin using one as soon as possible. It's simply not safe to walk a dog without a leash.
