<form action="ingrecaudacion2.php" METHOD=GET>
$sql = "SELECT * FROM 1_man_curso";
$con0 = mysql_query($sql,$link);

<?php
     echo '<select name="bcurso">';
       while ($row=mysql_fetch_array($con0)) {
         echo "<option value=".$row["cod"].">".$row["detalle"];
       }
     echo '</select>';
?>
<INPUT TYPE="HIDDEN" name="appalu" value="1">
</form>