Dog aggressive behavior to other dogs

My dog Stanley has very aggressive behavior towards other dogs! When I take him for walks or just tie him out in the front yard as soon as he see's another dog he start barking histercally and tries to attack the innocent dogs. Stanley is 9 years old and I adopted him from the animal shelter last year. I heard teaching and training older dogs is alot harder than puppies but I'm willing to dedicate myself to put an end to this behaviour. How can I teach him the proper behavior and put a final end to his aggressive behavoir so he can start making new dog friends?

Sarah and Stanley

Welcome to the board Sarah and Stanley ! Many of have had to and continue to deal with dog-on-dog aggression issues so please know that you are not alone and most often it can be "cured". I'm quite impressed with this:
DVD/VHS, ‘Love Them & Lead Them’ from Tenderfoot www.tenderfoottraining.com .

One of the key things I struggle(d) with is gaining my dog's respect as "pack leader" and trust that I will not allow harm to come to them. Having basic obedience under your belt is a good way to start. Have you been to any classes or worked on/ "perfected" basic commands ?