Sometimes, designing pretty forms with high usability is really hard even with lots of tutorials about how to design forms with CSS. Now, there is a very beautiful forms for you to download and use. You can also design your own theme for it if you do not like the default theme. Niceforms is a script that will replace the most commonly used form elements with custom designed ones.

Requirements: Firefox 1.5+, Internet Explorer 6.0+, Safari and Opera
Demo: http://www.badboy.ro/assets/articles/niceforms1.0/niceforms.html
License: License Free