PHP

In its most recent issue as of this posting (Issue #272), A List Apart released an article entitled A More Useful 404. This article laid forth a method of how to write a 404 page that's useful to both web administrators and users alike - one that will e-mail the admin an error e-mail letting them know what kind of 404 error there was, and a custom error message for the user that can help point them in the right direction, or at least let them know about the problem.