Portfolio help

hey, im trying to make a portfolio like the one shown on this page http://www.allcomm.co.uk/websitedesign.php but i really dont know where to start in making it move the way that one does, i know how to create the buttons and the components for it but i dont know how to make it so that when my mouse goes to the edge of the slide it scrolls automaticly, any help is much appreciated, thanks