Nope. Squirrelmail is just the web-frontend.
Email server are the SMTP (25) sending and POP3(110) / IMAP(143) receiving services.
Another solution is to run Exim under Cygwin. This is the only free windows based solution but is not trivial.
Also you have to manage your DNS server to specify/route all the incoming mails around the world to know this server.