Código PHP:
$pais[0]="Colom";
$pais[1]="Peru";
$pais[2]="Mex";
$sel= "Peru";
echo "<select>";
foreach($pais as $rows => $field)
echo ($field == $sel )?"<option value=\"$field\" selected=\"selected\">$field</option>":"<option value=\"$field\">$field</option>";
echo "</select>";