Motion tweens as they currently exist is in Flash CS4 are new to Flash. In previous versions of Flash, the term motion tween was used. However, it was used to describe what is currently called a classic tween.
The process for setting up a motion tween is basically the same as that for setting up a classic tween. The difference is how they function after they are set up. It is very easy to make a motion tween follow a curved path rather than a straight line path. Also, motion tweens can be affected in a more advanced fashion through the use of the Motion Editor. Motion Presets also exist now that apply pre-made motion tweens to your selected symbol instance.
Like classic tweens, motion tweens can be applied to any symbol instance.