Otra manera sería con un iframe o un popup:
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=utf-8" />
<title></title>
<script>
function getElementPosition() {
var offsetTrail = this;
var offsetLeft = 0;
var offsetTop = 0;
while (offsetTrail) {
offsetLeft += offsetTrail.offsetLeft;
offsetTop += offsetTrail.offsetTop;
offsetTrail = offsetTrail.offsetParent;
}
return {left:offsetLeft, top:offsetTop};
}
function t(id){return document.getElementById(id);}
function prev(en){
t(en).onmouseover=function(){
window.c=document.createElement('div');
c.style.position='absolute';
var pos=getElementPosition.call(t(en));
c.style.left=pos.left+10+'px';
c.style.top=pos.top+50+'px';
c.style.padding='2px';
c.style.border='1px solid #000';
c.innerHTML='<iframe width="500" height="300" frameborder="0" allowtransparency="true" src="'+t(en).href+'" />';
document.body.appendChild(c);
}
t(en).onmouseout=function(){
document.body.removeChild(window.c);
window.c=null;
}
}
onload=function(){prev('pepe');}
</script>
</head>
<body>
<a id="pepe" href="http://www.caricatos.net/">caricatos.net</a>
</body>
</html>