phpErrorDoc
We've all seen the ugly and uninformative Page Not Found error when a page no longer exists. This script was made in order to make error documents more informative and attractive for both the user and the webmaster. The messages, colors, and images are all customizable. It has languages support and works with register_globals=off. Additionally, it can log and/or e-mail an error when it occurs letting you know immediately if something is wrong on your site.