Fijate si te sirve algo así:
Código PHP:
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" />
<title></title>
<script>
function $(id){
return document.getElementById(id);
}
function addEvent(obj, evType, fn, useCapture){
if (obj.addEventListener){
obj.addEventListener(evType, fn, useCapture);
} else if (obj.attachEvent){
obj.attachEvent("on"+evType, fn);
} else {
obj['on'+evType]=fn;
}
}
function easing(prop,fin,tiempo,rozamiento,unidad){
var _this=this;
var i=setInterval(
function(){
_this.style[prop]=fin-(fin-parseInt(_this.style[prop]))*rozamiento+unidad;
if(parseInt(_this.style[prop])/fin*100 >= 99.9){
_this.style[prop]=fin+unidad;
clearInterval(i);
}
},tiempo);
}
window.onload=function(){
addEvent($('pp'), 'click',function(){easing.call($('pp'),'left',600,3.8,.8,'px');}, false);
}
</script>
</head>
<body>
<img style="cursor:pointer; position:absolute; left:0; top:0" id="pp" src="http://www.forosdelweb.com/customavatars/avatar65984_1.gif" />
</body>
</html>