Using mail() for mailist list app

Happy New Year everyone! Is the PHP mail() command robust enough to use in a little mailing list app? The app will basically send an HTML or Text e-mail to the member database of about 6,000 people. I'm using RedHat Linux 7.2 with PHP 4.2.2, by the way. I'm concerned I'll bog down my server if I issue the mail() command 6,000 times on our server, but, maybe it won't be a problem? Also, although I'm sending HTML e-mail, I'm not including attachments or inline graphics (only direct hotlinks to graphics on a web server). Will mail() still work okay for this, or do I need to use one of the various PHP e-mail classes available to send HTML e-mail? Any recommendations for online tutorials about building a mailing list manager using PHP would be much appreciated! Thanks! Monty