Sicilian_Babe - To develop your triceps, you want to have a routine made up of a mixture of cable work and free weights too. The triceps is made of three heads: the lateral head, medial head, and long head. While there is no one move that isolates a particular head of the triceps, there are moves that put more emphasis on a single head, for example the long head is best targeted by over-head extentions or using an underhand grip when doing cable pressdowns. I suggest you do atleast one or two compound movements like skull-crushers or close-grip bench presses to actually develop the muscle. Then move on to your cable pressdowns using a variation of one to three different grips and angles. Don't let certain words like "skull crusher" or "build muscle" scare you off with visions of chicks with huge guns. If you do what I said, using a light-to-moderate weight, in time you will get the results you are looking for. Don't forget your triceps need no more than 12-15 sets after warming up. Same goes for biceps.