You can do it with Perl...

* Get info about mails: Mail::POP3Client or Net::IMAP::Client. I've used both of them and they work very well.
* To send mails, you have more options: Mail::Sender, MIME::Lite. I prefer Mail::Sender over MIME::Lite, but that's just personal taste...

For all the CGI and output stuff, I would use CGI::Application (as a lightweight Webframework) and HTML::Template::Compiled (for templating).