Any dog trainers on this board?

I need some advice on my shih tzu. he is going to be two in december and is a bundle of joy. but he won't leave the cats alone and he has become aggressive toward some other dogs. the most important thing is breaking him from going after the cats. any suggestions? thanks.

hey nicole.  i sent you a pm...hope it helps

Is he crated when you aren't home?  I would probably try tethering him to you when you're home so he doesn't have the opportunity to go after the cats. If he tries, he'll get tugged back to you and you can give some sort of correction phrase (leave it, no kitty, something like that) and then put him in a sit stay.  Be sure to give him treats and/or praise when he does what you want him to.  I would also do the same thing when you are out and he is around other dogs.  The important thing is making it clear to him that you are the alpha and he is to listen to you.