PHPMail2Fax is a drop-in replacement for HylaFax's mail2fax written in PHP for the PHP CLI. It will support pdf and tiff and have the ability to handle MIME e-mail. All contributions are welcome.
mimx is an open-source, drop-in replacement for corporate communication servers such as Microsoft Exchange and Lotus Notes. mimx provides e-mail, chat, fax, network news, calendaring, etc. to clients such as Microsoft Outlook.