Drupal has a lot of forms to fill out and not all of them may be just the way you want or need them to be. Modifying forms is a topic that is often met with groans but once you understand the two methods to accomplish the task and the basic, underlying concepts, it really isn't that hard to do at all.

• Modifying Forms in Drupal 5 and 6 | Lullabot
• Using hook_theme to modify Drupal forms | adaptivethemes