Kodiak PHP - Kodiak PHP can run any PHP code directly (offline) on your iPad, no need for an internet connection.
Netbeans - NetBeans IDE 7.0. Develop desktop, mobile and web applications with Java, PHP, C/C++ and more. Runs on Windows, Linux, Mac OS X and Solaris. NetBeans IDE is open-source and free.
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.
Sublime Text - Sublime Text is a sophisticated text editor for code, html and prose - any kind of text file. You'll love the slick user interface and extraordinary features. Fully customizable with macros, and syntax highlighting for most major languages.
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
Eclipse IoT - Eclipse IoT provides the technology needed to build IoT Devices, Gateways, and Cloud Platforms.