Andreas Gohr has posted about a script he's created to act as a simple replacement for the PHP/MySQL database tool phpMyAdmin - what he calls MySimple.php.

Kaddi needed to fix something in her employer's database today. Unfortunately she had FTP access only. So the database change had to be made through a PHP script. [...] I looked for a basic MySQL PHP interface but couldn't find one. So I quickly wrote it my self.

He has a screenshot of the app in action included and you can grab the code from his wiki.