Can anyone help me with doing this?

Hi all,

found a technique that I have seen a bit and would like to implement for a piece I am doing. The link to the website that has it is below:

On this page is a photogallery at the bottom. When you rollover the images, they “highlight” which I know how to do. The bit I want to be able to replicate is the ability to move the mouse to the edge of the gallery and have it slide away from the “selected” edge. So for example, the further left you move your mouse, the faster the gallery “slides” or “scrolls” right. Then when you mouse towards the right, it slows down and scrolls towards the right.

I was wondering if anyone was able to give me some help on how it is done, or at least point me in the right direction (ie. tutorials etc.)

Thanks for any help