ReadyForm
ReadyForm is a Perl script that handles the email messaging of Web form results submitted by visitors to your site. Though this is typically accomplished with your existing server software, ReadyForm offers a friendlier, more informative email message and includes a built-in "thank you" page. This program has support for email programs that thread messages (i.e., put messages with the same subject indented under the first message). It also provides information such as IP address and the type of browser used to access the site.