Is your skeleton 1 piece or are you usiing a broken heirarchy (pieces of the skeleton that aren't attached to eachother)?

The option box under the paint tool will list all of the joints that you bound the skin to. If you choose the root joint (should be the base of the spine) then "select heirarchy" all of the joints will be selected when you bind the model to the skeleton. If you do this, all of the joints will show up in the paint window.

If your skeleton is broken into pieces; arm, leg, torso..., then each piece will have its own root joint. I'm not sure but I think if you "select all> joints" then ALL of the joints will be selected and you will be able to bind to all of the pieces at once. If not, then simply bind the model to each disconnected branch of the skeleton seperately.

If you're new to this then I doubt that you are using a broken heirarchy skeleton. They're a little advanced... If your skeleton is in 1 piece then you probably aren't choosing all of the joints when you bind the skin. Choose all the bones then choose the skin then go to the smooth bind menu.

One more thing; there are options when you bind the skin. You will want to bind to the entire skeleton with influence set to the nearest joint. There are other options that might work better for you so read about them. when you open the bind skin menu there is a help button that will take you directly to help on binding skin.

Go get 'em tiger!