$sql = "SELECT * FROM users WHERE username = $username AND password = $password";
$result = mysql_query($sql);
if (mysql_num_rows($result) > 0) {
	//good username + password
	$row = mysql_fetch_assoc($result);
	if ($row['admin'] == 1) {
echo '<a href=adm1n.php>Admin Page</a>';
		//is admin
	}
}