Simon Willison has a really cool article which points out simple things that you can do to make html forms extremely easy to use. This is a must read for any web developer.

My second article for SitePoint has been published: Simple tricks for more usable forms. It examines a whole bunch of CSS and Javascript tricks for improving the usability of web based forms without impairing their accessibility to clients that don't support those technologies. The article has already had some useful feedback on the forums, including the valuable observation that auto-selecting the contents of a form field when it receives the focus can have a negative effect on the usability of Unix browsers, where mouse buttons are frequently used for coping and pasting.

[Simon Willison's Weblog]