The DeveloperTutorials website has a new article that steps you through the creation of an autoresponder script for an email account (in qmail).
It's very convenient for users to be able to communicate with web applications (or businesses) via email, but it's not always easy for the employees of the company to respond. Some of the email requests could be complex, and others could be simple but occur very frequently. So it's a real advantage when we can write scripts to respond to user emails for us.
The tutorial sets up a basic structure for you to work from including places for the addresses and extra headers for the response. You can also download the code to have it to follow along with (or play around with yourself).