Xdebug

Xdebug
http://www.xdebug.org/

PECL :: Package :: Xdebug
http://pecl.php.net/package/Xdebug

phpDocumentor

phpDocumentor: The complete documentation solution for PHP
http://phpdoc.org/

SourceForge.net: PhpDocumentor
http://sourceforge.net/projects/phpdocu/

APD - Advanced PHP Debugger

PECL :: Package :: apd
http://pecl.php.net/package/apd

Advanced PHP debugger
http://php.s3.to/man/ref.apd.html

APC - Alternative PHP Cache

PECL :: Package :: APC
http://pecl.php.net/package/APC

PHP Accelerator

ionCube社が無償で提供しているソフトウェア．
The ionCube PHP Accelerator: Home
http://www.php-accelerator.co.uk/

ionCube PHP Encoding and Acceleration: ionCube PHP Accelerator
http://www.ioncube.jp/accelerator/

Reference

Do You PHP? - Xdebugを導入してみる - JavaのStackTraceが欲しい！
http://www.doyouphp.jp/tips/tips_xdebug.shtml
phpDocumentor - phpspot
http://phpspot.net/php/pgphpDocumentor.html

via

FrOSCon "PHP best practices"資料 (SOLVALOU.NET)
http://solvalou.net/2006/06/froscon_php_best_practices.html