In Using HTML_Quickform for Form Processing, the author introduces you to a very powerful (and widely used) PEAR package to help you keep a consistent look across all of the forms of your site (not to mention the functionality).

THE HTML_QUICKFORM module makes working with HTML forms easier. Instead of printing form elements one by one, you use its methods to define a form structure that you can print all at once. HTML_QuickForm automatically preserves defaults across form element submission, displays error messages, assures a consistent look to your forms, and simplifies file uploads.

They continue on , demonstrating how easy it is for a developer to build an application/form for a specific task, and get it up and working in no time at all. They show you some sample code - everything from a simple text entry up to hiddens and file fields.