On WebReference.com today, there's this new tutorial with an introduction to getting PHP to interact with web forms.

HTML forms are one of the key ingredients of any dynamic website because they can enable the users of a site to interact with it. Otherwise, websites are more or less static:They may be driven by a database and, therefore, regularly changing, but they look the same for each and every visitor. HTML forms can change that; therefore, using data from forms from within PHP is very important.

They give examples of how to send data back to a script from a form, reading that data (using superglobals), and what data will be returned from each form element type. From there, they get into specifics like dealing with magic quotes and saving the form data into a cookie...