The best exercice ever for that is the Scott bench (preacher bench).
You take a weight about 20 pounds lighter then you are used too and you curl up and down. When you are down, you open your hands and let the bar roll down untill it is almost at the top of your fingers. Then you close your hands again and restart. The pump in your forearms is unbelievable.
Oh......& this is off the subject.......did you know there was an Elite Fitness Board called "Training Discussion Board?"...do a search over there or do a post over there.
"While the peak of your bicepts are largely determined by genetics, doing a variety of exercies could help." Try hammer curls, and vary up your workout.