Easing a movie clip into place using actionscript

Ok, I’ve only ever used tweening to move an object on the stage which always looks choppy. Say I have a movie clip that is just off the stage and I want to bring it to the center of the stage nice and smoothly starting slowly, getting faster and the slowing down, what actionscript would I have to use.

I really would appreciate the help as I am getting sick of the choppy look. I have searched for tutorials but found only ones that make objects follow a mouse smoothly.

In fact to make it easier, here’s a FLA which uses traditional tweening to move the object, what must I do with it to get rid of the tweening and replace it with a nice smooth actionscript?

Many thanks in advance