Digett.com: How to Theme the Comment Form in Drupal 6
If you're a Drupal user and are looking for a way to change up that standard comment form that comes pre-loaded in the site, you should check out this new post on the Digett blog about the handy hook_form_alter function.
I've grown to have an affinity for Drupal's hook_form_alter function. Truly, modifying a form doesn't have to be as complicated as it may seem. One of the most generic Drupal forms (in my opinion) is the pesky comment form. Out of the box, it comes complete with name, email, homepage, subject, and comment fields.
A few snippets of code included in the post show you how to customize the form by removing some fields, changing labels on others and update the value of one of the buttons - all with a simple implementation of a hook theme.