Anthony,
I tried and didn’t work. Any other suggestion? If I use the library that you suggested earlier, does it work to send messages that are POST? Can I merge the HTML code with the code of the library?
I’d suggest you carry on with the book and forget about this for now. The main reason is that if it’s a decent book then all those questions will be answered and it should be somewhat more obvious how to approach using a library with your script.
But in case you won’t take advice (offered twice now :P):
There are no other suggestions, either install a smtp server or use a third party lib that handles smtp auth.
Messages aren’t POST, data is POSTed to your script, you do stuff with it, like send emails.
No. At the top of your script, separate from the html, you should put the logic code that deals with POST vars and sending emails etc. You should never mix more than echo and control flow (loops etc) with html.