Top PHP Studio is an Integrated Development Environment for PHP. Top PHP Studio provides comprehensive and easy-to-use solution for editing, testing and deploying PHP based web applications.
Main features of Top PHP Studio includes:

Executing PHP scripts through the internal HTTP server
Live preview of scripts in the internal browser
Built-in FTP client for handling files on remote servers
Code explorer
Function and parameter completion for standard PHP functions
Syntax checking for PHP code
HTML tag completion
Visual file comparison utility
Configurable syntax highlighting for PHP, HTML, SQL, CSS...
Integration with PHP documentation

Features:

Internal HTTP server: Users may test their PHP scripts without a need for external HTTP server. Users may also disable this feature to test your PHP scripts with external HTTP server
Internal browser (requires MSIE 4.0 or higher): Users easily preview the output of PHP scripts
Built-in FTP client. You can work with the files on remote server
Customizable syntax highlighting for PHP, SQL, HTML, XML, Cascading Style Sheet (CSS), JavaScript, Perl, Python and Java
Integration with PHP documentation: You can press F1 to search inside PHP documentation (requires CHM version of PHP Help)
PHP function and parameter completion: You can quickly see PHP function list by pressing Ctrl+Enter and Shift+Ctrl+Enter for a hint pop-up containing parameter reference for selected function.
Visual file comparison utility
Server explorer panel: You can easily access the files which will be served
File explorer: You can easily access local file system while you are working with Top PHP Studio
Code snippets: You can easily access CSS and HTML tags
Advanced text editing capabilities (Multiply undo/redo, find/replace, indent/unindent ...)
Automatic correction (similar to MS Word).
Tabbed multiply document interface (MDI)
Backup & automatic saving of files
Automatic parentheses highlighting
Column mode editing: While pressing Alt key, you can edit in column mode
Bookmarks
Highly Customizable