I've been having some trouble finding some information on how to set up a automatic email generating script.

Basically what I am trying to achieve, is when a website visitor submits their email (into a form) - they automatically get sent an email that contains a downloadable link (the link doesn't need to change).

The main purpose of this is to retain the email addresses of anyone who wants to download this file.

So in short, someone visits the website - puts their email address into a form and automatically receives an email with a link in it.

Does anyone have any sources on how to go about this? Any help is appreciated.

Thanks a lot.