Probá 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=utf-8" />
<title>Documento sin título</title>
<style>
.flip1{
-moz-transform: scaleX(-1); /* Gecko */
-o-transform: scaleX(-1); /* Operah */
-webkit-transform: scaleX(-1); /* webkit */
transform: scaleX(-1); /* standard */
filter: FlipH; /* IE 6/7/8 */
}
.flip2{
direction: rtl;
unicode-bidi: bidi-override;
}
</style>
</head>
<body>
<form action="" method="get"><input onkeyup="document.getElementById('uno').innerHTML=document.getElementById('dos').innerHTML=this.value" style="width:300px" name="" type="text" />
</form>
<div id="uno" class="flip1" style=" text-align:right"></div>
<div id="dos" class="flip2" style=" text-align:left"></div>
</body>
</html>
Podés elegir la clase css que más te guste :)