39875 PHP form to email on Plesk

I have Plesk 7.5 on windows 2003 all working fine with pop3 emails and websites. I can not get my php appl like PHPBB, Joomla feed back forms etc to send out emails, like the forgot password email, new account email, feedback form email. I need a server admin or php guru to show me how to make my php email out correctly, it could be a plesk setting or a [login to view URL] setting.