Configure Eclipse PDT / XDebug for PHP debugging
Eclipse PDT settings
A suggestion: don't set "workspace" location the same as real project files reside. Seperate "Eclipse projects files" with actual source files.
Take PHP 5.4 custom installation as an example. The executable should be properly configured in Preference tab.
Then configure proper base site url, especially it is not "localhost". As in this sample the launched site is "http://phplab/".
Configure general debug settings ( assign XDebug as debugger ):
As per web app project, should set proper base url. If directly launching web app from "http://phplab/" , the base path should be set with "/".

Important XDebug settings under PHP engine
1. Download proper XDebug dll, set it as Zend extension in root php.ini:
zend_extension = ext\php_xdebug-2.2.0RC1-5.4-vc9-nts.dll
Note zend extension doesn't rely on "extension_dir" so here should explicitly assign the relative directory part "ext", otherwise PHP can't position the dll path.
2. Must set xdebug.remote_enable = On ( in root level or per site level ( user.ini ) ) ! Otherwise when starting "remote launch" ( this is essential for web server debugging ) , the PDT status always stays here and can't get further response:
Debugging needs switching to "Debug" perspective; otherwise stays in "PHP" perspective for maintaining project or handling sources.