Schogini

Creating a theme for a form in Drupal 6 is slightly different from Drupal 5.

Steps on how to theme a form in Drupal 6:

1. Register the theme file.
   Use the hook_theme() function to register the theme for  the form. More information on hook_theme() can be got from here: http://api.drupal.org/api/function/hook_theme

   NOTE: myform1_form and myform2_form are the form ids of the forms you want to theme

   function mymodule_theme()
   {
       $themes = array(
           'myform1_form' => array(
               'arguments' => array('form'),
               'function' => 'mytheme_myform1_form',
           ),
           'myform2_form' => array(
               'arguments' => array('form'),
               'function' => 'mytheme_myform2_form',
           ),
       );
       return( $themes );
   }
   

2. Define the callback function. Pass parameters to the theme file and render the file.

   function mytheme_ myform1_form($form)
   {
       drupal_add_css(drupal_get_path('module', 'mymodule') .'/mymodule-form.css');
       drupal_add_js(drupal_get_path('module', 'mymodule') .'/mymodule-form.js');
       return theme_render_template(path_to_theme() . '/mytemplate.tpl.php', array('form' => $form));
   }
   NOTE: It is important to pass the form parameter to the template file as array('form' => $form)
   instead of directly passing $form
   For more information on theme_render_template() check this http://api.drupal.org/api/function/theme_render_template/6
   

3. Template file.

   <div class="onelinedd">
       	<div class="onedd">
           	<div class="labels">
    		  <div>Form Field 1</div>
    		  <?php echo drupal_render($form['form_field_1']); ?>
    		</div>
           </div>
       	<div class="onedd">
           	<div class="labels">
    		  <div>Form Field 2</div>
    		  <?php echo drupal_render($form['form_field_2']); ?>
    		</div>
           </div>
       	<div class="onedd">
    	  <?php echo drupal_render($form['submit']); ?>
           </div>
       </div>
   

4. Clear cache. Admin -> Site Configuration -> Performance -> Clear Cache

I am sure there must be an better way to do this but, after hours of searching and trying this is what worked for me!

Tips on how to theme a form were taken from these links:

http://agaric.com/note/how-theme-drupal-form

http://drupal.org/node/228189

http://api.drupal.org/api/function/hook_theme

http://api.drupal.org/api/function/theme_render_template/6