Built into PHP, no. Only FTP and sftp (via ssh2) are internally supported; however, ssh2 is a PECL extension, and FTP has to be enabled.
As for TFTP, you might look over at pecl.php.net and see if there's something there. You might try googling for a php 5 class implementation of tftp; however, I bet you're going to have to create your own class for it.
