Fijate si te sirve:
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>Documento sin título</title>
</head>
<body>
<form name="form1" method="post" action="">
<select name="select" onchange="if(!this.selectedIndex){PP.disabled=1;PP.value='...';return;};PP.disabled=0;var l=this[[this.selectedIndex]].getAttribute('title');PP.value='Ir a '+l;PP.onclick=function(){window.location=l;}">
<option>--------</option>
<option value="valor=303,media=6.20" title="http://www.google.com">CHARGE 6.20</option>
<option value="valor=n,media=n" title="http://www.yahoo.com">FOO 7.0</option>
</select>
<input name="PP" type="button" value="..." disabled="disabled" />
</form>
</body>
</html>