How to speed up or slow down animation

[modulor]

I'm trying to make an object speed up or slow down gradually
and I wonder how could I do. There's an exemple of this type of effect at http://www.submethod.com. When you arrive on the site, at the right of the page there is a small grey circle that moves up and down slowing down and accelerating. That exactly what I'm trying to do. Could someone help me?

Thanks.

[CNO]

Modulor,
You probably want to play around with the ease-in and ease-out settings of your animations motion tween to get these effects. You should also increase the nuber of keyframes to get a slower motion and use fewer keyframes for more rapid movements.
Hope this helps,