I would recommend in your case that you look at using PHP as core backend and (x)html+javascript+ajax for frontend and front-to-backend communications.
Ajax is very good for dynamic pages where you do not want page reloads etc.
You could have a local smtp server to send the email, but most internet providers would not allow this. If the later is the case you need to use the internet providers smtp, alternatively allow the configuration of smtp within the user interface.
PHP has builtin classes to send mail which makes this process easy in either case.
Receiving mail and parsing them correctly is just a matter of understanding the correct protocols. (pop3 / exchange and so on).
I know this wasn't a straightforward answer, but I hope it gave at least some insight.