Código PHP:
<?php
if($_GET['country'])
$pais=$_GET['country'];
else
$pais="colombia"; ?>
<select name="country">
<option value="">seleccione</option>
<?
require_once ("conectar.php");
$rs = mysql_query("select * from country", $link);
while ( $vec = mysql_fetch_array($rs) )
{
echo "<option value=$vec[id_country] ";
if ($vec[nom_country] == $pais)
echo " selected";
echo " >".$vec[nom_country]."</option>";
}
?>
</select>
Chaop!