I am a fan of symfony project . So I used to watch whats happening there . Recently I was reading a blog post by Fabien Potencier the CEO of sensio labs and the lead developer of symfony framework which is RAD tool for PHP . It was about the swiftmailer . The swiftmailer is a PHP5 powerful SMTP mailing system . Its used by the project symfony framework . You don't need symfony to send mail using swiftmailer . Its developed by Chris Corbyn and now the project manager is Fabien Potencier .

It has lots of nice fatures some are

    *  Send emails using SMTP, sendmail, postfix or a custom Transport implementation of your own
    * Support servers that require username & password and/or encryption
    * Protect from header injection attacks without stripping request data content
    * Send MIME compliant HTML/multipart emails
    * Use event-driven plugins to customize the library
    * Handle large attachments and inline/embedded images with low memory use

Please do visit the site http://swiftmailer.org/ for more information and how to use it .