I have this "condition", but it has sort of balanced itself out now. What I did was just do stuff for both arms as best you can, and when you do your stuff for each arm work them out the same. So i use the same weight for both my right & my left, even though my right is stronger. As a result of doing this my arms are almost equal now. The only bad part is my left arm is a bit bigger than my right (19" left, 18 1/4" right. I know this because i just had my measurements taken
). Thats the only bad thing, but its not to the point where its really noticable.
Press hard, keep the weight up on the weaker arm and just stick with it. Always work your weakest part the hardest. After a while it will no longer be your weakest part.
I basically apply the same principle to all body parts. For example my right shoulder is slightly stronger than my left. Just work it hard and have the stronger keep pace so that when the weaker catches up the "stronger" hasnt been slacking and will be ready to go hard again.
Hope that helps.