To move the most recently created joint in the joint chain you are drawing
 -click the joint (transform manipulators appear), then drag it to its new position.
-click the joint (transform manipulators appear), then drag it to its new position. 
                   (Linux and Windows) or
 (Linux and Windows) or  (Mac OS X) key (transform manipulators appear), drag the joint to its new position, then press
 (Mac OS X) key (transform manipulators appear), drag the joint to its new position, then press  or
 or  again.
 again. 
                  After you move the current joint, click in the scene view to continue creating joints for your joint chain.