Can anyone help me add and automatic scrolling effect to the following javascript. This code is on an older site using jquery 1.4.3. I was hoping it was just something I could simply add to this existing js so I don't have to redo the entire slideshow. Thanks!

Code:
<script type="text/javascript">
$(document).ready(function() {
// Save the jQuery objects for later use.
var outer	= $("#preview_outer");
var arrow	= $("#arrow");
var thumbs	= $("#thumbs span");

var preview_pos;
var preview_els	= $("#preview_inner div");
var image_width	= preview_els.eq(0).width(); // Get width of imaages

// Hook up the click event
thumbs.click(function() {
// Get position of current image
preview_pos = preview_els.eq( thumbs.index( this) ).position();

// Animate them!
outer.stop().animate( {'scrollLeft' : preview_pos.left},	500 );
arrow.stop().animate( {'left' : $(this).position().left },	500 );
});

// Reset positions on load
arrow.css( {'left' : thumbs.eq(0).position().left } ).show();
outer.animate( {'scrollLeft' : 0}, 0 );

// Set initial width
$("#preview_inner").css('width', preview_els.length * image_width);
});
</script>