I want to briefly walk through making a 'skeleton' module for Drupal 6x.

1. You want to go ahead and create a folder named "custom" in /sites/default/modules/

2. Create a folder named "skeleton", the folder name will be the module name.

3. You should make 4 files in the skeleton folder, skeleton.info, skeleton.module, skeleton.inc, and skeleton_example.tpl.php

4. The .info file describes the module to drupal, the .module file is where your hooks will go, and the .inc file is a place to put any extra helper functions.

skeleton.info

; $Id$ 
name = skeleton 
description = Empty starter module. 
core = 6.x

skeleton.inc

<?php
/* Put any helper functions or other stuff you want in here */

skeleton_example.tpl.php

<div id="skeleton_example">
   <b>Skeleton Example Template File</b> 
</div>

And finally, the skeleton.module file

<?php
// $Id: skeleton.module

/**
* @file
* Skeleton Module File.
*/

//pull in our include file
module_load_include('inc', 'skeleton');

/* This is where you can start calling in the drupal hooks that make up your module
	some example hooks like hook_user, hook_menu, hook_perm are listed below
*/

//module permissions
function skeleton_perm() {
	return array('skeleton module permission');
}

//lets get some sweet sweet menu action going
function skeleton_menu() {
	
	$items['skeleton/example'] = array(
		'title' => 'Skeleton Module Hook Menu Example',
		'description' => t('Skeleton Module Hook Menu Example'),		
		'page callback' => 'skeleton_example', // 
		'access callback' => 'user_access',
		'access arguments' => array('skeleton module permission'), // or use hook_perm() to make your own
		'type' => MENU_CALLBACK,
	);
	return $items;
}


//hook_theme
function skeleton_theme($existing, $type, $theme, $path) {
	return array(
		'skeleton_example' => array(
		'arguments' => array('options' => NULL),
		'template' => 'skeleton_example',
		),
	);
}

You should now be able to enable the module, and make sure to assign the permission we created to whatever user you are. Then navigate to the /skeleton/example page and you should see what we put in the template file. You can download the full skeleton module example HERE.