This is a pretty good article as it illustrates some of the basics for medicine ball training without getting too crazy with scientific termonilogy; so it is easy to use.
I use the medicine ball as part of my individual periods with the Dline; I feel it is an excellent tool for building explosive and functional football strength. The first drill we do is a simple caber toss (or overhead toss as the article calls it) where the athlete starts with the medicine ball overhead, swings it down between his legs doing a deep knee bend (but keeping the back straight), and then explodes upwards throwing the ball as high as possible. The throw should be explosive enough that the athlete actually leaves the ground. It is important that the athlete start with the medicine ball overhead and reverse the momentum of the ball on the throw . . . this makes it a plyometric movement. Generally I will have them do 3 sets of 3 reps.
The other drill I do with the Dline, which I prefer as I feel it is more sport specific, is a throw for distance off the chest. I make sure the athlete positions his feet just as he would from his stance and also positions his hands on the medicine ball just as he would position his hands just as he does when taking on a block (narrow grip, thumbs pointing up, elbows tight to the body). Once he is in the right position he does a deep knee bend and explodes forward throwing the medicine ball as far as possible. I generally make this into a throwing contest among the Dlinemen to make the drill a little more interesting and to get their best efforts via natural competitiveness. Furthermore, this drill is a good stage in the teaching progression when we are working fire out, initial hand strike, and first step. Another variation on this would to have them sprint a certain distance right after the explosive throw.
Here is the link to the training forum where the entire article can be seen followed by a note about the author. . . enjoy: