One Step: Add this code to the body section of your page.

//Comment trail script- By Kurt (kurt.grigg@virgin.net)
//Script featured on Dynamic Drive
//Visit http://www.dynamicdrive.com for this script and more

colours=new Array('#ff0000','#00ff00','#ffffff','#ff00ff','#ffa500','#ffff00','#00ff00','#ffffff','ff00ff')
n = 10;
y = 0;
x = 0;
n6=(document.getElementById&&!document.all);
ns=(document.layers);
ie=(document.all);
d=(ns||ie)?'document.':'document.getElementById("';
a=(ns||n6)?'':'all.';
n6r=(n6)?'")':'';
s=(ns)?'':'.style';
if (ns){
for (i = 0; i < n; i++)
document.write('<layer name="dots'+i+'" top=0 left=0 width='+i/2+' height='+i/2+' bgcolor=#ff0000></layer>');
}
if (ie)
document.write('<div id="con" style="position:absolute;top:0px;left:0px"><div style="position:relative">');
if (ie||n6){
for (i = 0; i < n; i++)
document.write('<div id="dots'+i+'" style="position:absolute;top:0px;left:0px;width:'+i/2+'px;height:'+i/2+'px;background:#ff0000;font-size:'+i/2+'"></div>');
}
if (ie)
document.write('</div></div>');
(ns||n6)?window.captureEvents(Event.MOUSEMOVE):0;
function Mouse(evnt){
y = (ns||n6)?evnt.pageY+4 - window.pageYOffset:event.y+4;
x = (ns||n6)?evnt.pageX+1:event.x+1;
}
(ns)?window.onMouseMove=Mouse:document.onmousemove=Mouse;
function animate(){
o=(ns||n6)?window.pageYOffset:0;
if (ie)con.style.top=document.body.scrollTop;
for (i = 0; i < n; i++){
var temp1 = eval(d+a+"dots"+i+n6r+s);

randcolours = colours[Math.floor(Math.random()*colours.length)];
(ns)?temp1.bgColor = randcolours:temp1.background = randcolours; 
if (i < n-1){
 var temp2 = eval(d+a+"dots"+(i+1)+n6r+s);
 temp1.top = parseInt(temp2.top);
 temp1.left = parseInt(temp2.left);
 } 
else{
 temp1.top = y+o;
 temp1.left = x;
 }
}
setTimeout("animate()",10);
}
animate();
// -->
</script>