Atrise PHP Script Debugger
Atrise PHP Script Debugger is a debug script for your PHP projects. It can help you to show PHP variables, debug string output, script execution time, the page source and other information that helps you in your PHP development. Features of the PHP Debugger: Handy output with debug points with... Simply place a few files to your PHP project to begin.
http://www.atrise.com/php-script-debugger/file.php - 11Kb - Download - Screenshot

PHP Expert Editor
PHP Expert Editor is an easy-to-use PHP IDE (Integrated Development Environment) for Windows with UTF-8 support. This Editor specially designed for PHP-masters and has a nice features for beginners and professional programmers. PHP Expert Editor has internal HTTP-server and Debugger to run, test... The PHP Syntax Check, internal browser, Code Explorer, File Explorer, FTP client with SFTP support, Project Explorer, Code Templates, customizable code highlighting, quick navigation in code, and much more.
http://www.ankord.com/download/phpxedit_40b.zip - 3Mb - Download - Screenshot

Expert Debugger
Expert Debugger is a free easy-to-use tool for debugging PHP scripts. Expert Debugger uses the DBG PHP Debugger and allow to debug scripts via network or on local computer. You can run scripts in step-by-step mode and to trace values of any variables and script output. ... The debugger has a comfortable interface and can be integrated with IDE or editors.
http://www.ankord.com/download/phpxdbg_20.zip - 1Mb - Download

PHP-Script-Logit
PHP-Script-Logit is a logging tool for PHP debugging. For those of you who, like me, develop PHP in Notepad, it's really nice to have a little logging tool to keep a watch on what is going on in my PHP scripts. Just use the simple Logit function together with this desktop tool to monitor your... The PHP logging script is under ten lines of PHP. ... The desktop app is very simple and requires no installation.
http://free-backup.info/apps/php-script-logit.exe - 173Kb - Download - Screenshot

RegexBuddy
RegexBuddy is your perfect companion for working with regular expressions. Easily create regular expressions that match exactly what you want. Clearly understand complex regexes written by others. Use plain English building blocks instead of or in addition to the standard regex syntax. ... Use the regex in your source code with code snippets automatically adjusted to the particulars of C#, Visual Basic, Java, C, C++, Delphi, Perl, PHP, Python, JavaScript, VBScript, Ruby, etc. ... Debug without guesswork by stepping through the actual matching process.
http://www.regexbuddy.com/cgi-bin/SetupRegexBuddyDemo.exe - 3Mb - Download - Screenshot

Oceantiger's Editor
Edit Java, html, xml, perl, php, css and text documents. Color highlighting for the mentioned languages and posibility to define your own color highlighting for other languages. Other features in this program includes: tools to compile - debug and run java documents, undo / redo feature, tools... In html and xml documents, the end tag will be inserted automatically with the autotag completion feature.
http://www.oceantiger-software.com/otsEditor/otsEditor-setup.exe - 2Mb - Download - Screenshot

Zend Studio
Zend Studio is the only Integrated Development Environment (IDE) available for professional developers that encompasses all the development components necessary for the full PHP application lifecycle. Through a comprehensive set of editing, debugging, analysis, optimization and database tools,...
http://downloads.zend.com/studio/5.1.0/ZendStudio-5_1_0a.exe - 16Mb - Download - Screenshot

Zend Studio for Linux
Zend Studio is the only Integrated Development Environment (IDE) available for professional developers that encompasses all the development components necessary for the full PHP application lifecycle. Through a comprehensive set of editing, debugging, analysis, optimization and database tools,...
http://downloads.zend.com/studio/5.1.0/ZendStudio-5_1_0.tar.gz - 16Mb - Download - Screenshot

Zend Studio for Mac
Zend Studio is the only Integrated Development Environment (IDE) available for professional developers that encompasses all the development components necessary for the full PHP application lifecycle. Through a comprehensive set of editing, debugging, analysis, optimization and database tools,...
http://downloads.zend.com/studio/5...ndStudio-5_2_0-Mac_OS_X_POWER.zip - 16Mb - Download - Screenshot

Complete Mail Server
Complete Mail Server is high-performance professional SMTP/POP3 server software engineered for corporations and ISPs to satisfy business needs in ultra fast, flexible and reliable mail server. It works along with any email program or mailer and offers a lot of security features and options to... For example, this feature can be useful for developers to debug the scripts written with PHP, Perl, Java or other software. ... While test mode is activated, the server accepts your email messages, stores them in the queue but nothing delivers to the actual recipients.
http://www.softfolder.com/download/cmailsrv.zip - 2Mb - Download - Screenshot