Eh, I'm no Yoda but here is a way to do tweening:
http://dl.dropbox.com/u/5426011/examples%208/tween.capx
In a nutshell I used another sprite to act as a keyframe. In the events the two closest keyframes are selected and the Sprites are linearly interpolated from key to key.
EDIT:
Here is an simple example just doing what you asked:
http://dl.dropbox.com/u/5426011/examples%208/tween_simple.capx
and for fun I was tinkering with my original example:
http://dl.dropbox.com/u/5426011/examples%208/tween2.capx
Thanks! Iv used your 'Tween Simple.capx' (Oops! Try Again)to achieve a Card Flip effect. Is there a way to make the sprite flip to reveal the other side? Im trying to switch between frames in the animation editor, from front to back.
dropbox.com/s/5wr1xcn3lcajg0m/CardFlip.capx