duece, you are right to be concerned. Right now, your puppy is giving you warnings. Very shortly he will move into biting. When a dog that young shows aggression, it is due to human error, not his. It is a training and leadership problem. Your little guy appears to be under the impression that he is the one in charge. You would do well to find out from your vet, friends, or neighbors if there are puppy training classes in your area. Dogs view the world differently than we do. They are genetically predisposed to viewing the world in a pack structure. There is a male and a female as pack leaders and all the other dogs find their place within the pack ranking. You and all of your family members need to learn how to be the top dogs and to get him to understand that he is the lowest man in the pack rank. Here is a link to a website that will help you get understand what you need to do to accomplish this.
Establishing and Keeping Alpha Position, Letting your dog know you are the boss
If you can't afford training classes you might want to invest in some books or a training DVD. Labman, our resident dog expert likes the DVD showing the Monks of New Skete techniques. Unfortunately, they don't sell the DVD on their web site, but you can purchase one of their books or CDs from their site. The DVD that exists is sold by outside sources. You can do an online search and see where the best buy is. Labman also has an excellent list of books on his sticky:
http://www.askmehelpdesk.com/dogs/in...tml#post251804