HTTP 404 Email Notifier is a WordPress plugin by carlthome that keeps track of broken links on your WordPress site by sending admin email notifications whenever a visitor ends up on your theme’s 404-page. The email contains information about the broken link, where it was found and by whom.
No new administration screen. This plugin does not add yet another options page to your already cluttered admin area.
Clean install and uninstall. This plugin does not modify your database at all.