Kodiak PHP - Kodiak PHP can run any PHP code directly (offline) on your iPad, no need for an internet connection.

CodeLobster PHP Edition - CodeLobster - Free portable PHP IDE with support Drupal, Smarty, Twig, WordPress, Joomla, JQuery, CodeIgniter, HTML, CSS, JavaScript, AngularJS, CakePHP, Facebook, Laravel, Phalcon, Symfony, Yii

Coder - The Cloud IDE, Solved

Rapid PHP - Rapid PHP editor is the world's fastest and lightest PHP IDE for Windows with code intelligence and tools for PHP, HTML, CSS, and JavaScript, including PHP debugger, FTP/SFTP client, UTF-8 support and more.

Nova - Nova is an all-in-one productivity tool. With Nova you can freely choose which components to add to your projects and which you need for productivity, without any pre-set template.

NuSphere PhpEd - PhpED - PHP IDE integrated development environment for developing web sites using PHP, HTML, Perl, JScript and CSS that combines a comfortable editor, debugger, profiler with the MySQl, PostrgeSQL database support based on easy wizards and tutorials.