This is a tutorial on how to create a basic contact form using PHP and is a follow on tutorial for the HTML Contact Form tutorial.
The tutorial doesnt go through how to add validation or any other fancy features, but it will give you a really good idea how the form works, and give you a few basic idea on how PHP works.
Steps
Create a new folder on your desktop called "Contact"
Move your contact form HTML file into that folder
Create a new text file and name it "contact.php"
Move the contact.php file into the Contact folder
Paste the code below into the contact.php
Replace the email subject and webMaster email address with your own.
Near the bottom of the code there is a phrase that says "html results page", replace that with the HTML for your sucess page, or just type a sucess phrase as an alternative.