Sending mail from a web page using a php script is easy, but can be dangerous if not done right.
http://php.net/manual/en/ref.mail.php
http://php.net/manual/en/function.mail.php
Useful guides and tips in securing PHP e-mail script
http://www.tutorialtastic.co.uk/page/php_mail_form_secure_and_protected
http://www.nyphp.org/phundamentals/email_header_injection.php
http://www.securephpwiki.com/index.php/Email_Injection
