How to theme a form in Drupal 6

var fbShare = {url: ‘http://sree.cc/drupal/how-to-theme-a-form-in-drupal-6′,size:’large’} 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:

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 [...]