Attacking

Our young (2 years old) male cat, Junee is attacking our other female cat, Tobey who is 4 years old. Both of the cats are indoor cats. Most of the time Junee is licking Tobey and Tobey is licking Junee and cleaning each other. Then the other times Junee is chasing Tobey and jumping on her back and biting and fighting her. When our neighbor's dog comes over on our porch, Junee will attack our front door and start hissing until the dog gets off the porch and when I stop playing with the dog. The most extreme case was that Junee attacked a baby that was over visiting. I was not home but my partner and her friend were at home playing with the baby. The baby was cooing loudly and happily and Junee came and attacked the baby. Good thing Junee has been declawed, however he attempted to bite the baby along with violently jumping at the baby and hissing and spitting. Finally our female cat came to attack him to let the mother and the baby in safe hiding until he could be isolated into another room. Now we are scared because my partner is expecting and we do not know what to do with Junee. When he is not showing this type of behavior he is cuddling and being loving with his two mothers. We do not want to give away our cat but where do we draw the line because of our baby that is coming in Febuary 2009. Any suggestions on handling Junee's behaviors and any suggestions on preventing this from happening to our new born baby?