What is the recommended way to create plugin administration forms?

I have seen and been using the following technique for adding php scripts to my plugin for handling custom forms in a wordpress plugin.

from the quizzin plugin:

$code_pages = array('quiz_form.php','quiz_action.php', 'question_form.php', 'question.php');
        foreach($code_pages as $code_page) {
            $hookname = get_plugin_page_hookname("quizzin/$code_page", '' );
            $_registered_pages[$hookname] = true;

For example, the ‘quiz_action.php’ is later used as the target for an administration form (these forms are used only in wp-admin)

  <form name="post" action="<?php echo $GLOBALS['my_plugin_folder'] ?>/quiz_action.php" method="post" id="post">

UPDATE: This method is discussed here – Admin config screen without menu

The final comment below by a WordPress core dev seems to discourage this:

http://wordpress.org/support/topic/how-can-i-execute-php-scripts-in-my-plugin-folder

So what is best practice here? Should administration forms be posting to wp-admin/admin.php?action=foo or wp-admin/edit.php?action=bar. How does one register these actions? Is this documented anywhere? To be clear, these files should not be linked from an admin menu.

I’m using WordPress 3.0.4

Thanks!

I personally just add a menu link and in the function for it handle the form. With $_SERVER[‘REQUEST_URI’] as the action. Example below.

add_action("admin_menu", "menu" );
function menu(){
    add_menu_page('Test form', 'Test form', 'manage_options', 'show_form' );
}
function show_form(){
    if ( $_SERVER["REQUEST_METHOD"] == "POST" ){
            print "do stuff";
    } else {
         ?><form method="post" action="<?php echo $_SERVER['REQUEST_URI']; ?>"><input type="submit" /></form><?php
        }
}