Just installed Eclipse-Juno and the associated PHP Development Tools (PDT) SDK from org.eclipse.php.sdk.feature.group.
php --version yields:
PHP 5.4.8-1~precise+1 (cli) (built: Oct 29 2012 14:58:46)
Copyright (c) 1997-2012 The PHP Group
Zend Engine v2.4.0, Copyright (c) 1998-2012 Zend Technologies
with Xdebug v2.2.0, Copyright (c) 2002-2012, by Derick Rethans
Php -m indicates that xdebug is loaded.
[Zend Modules]
Xdebug
In eclipse, Windows->Preferences->Php->Debug->PHP Debubber is Xdebug.
However, none of my breakpoints hit.
What should I check to make debug breakpoints work for PHP on Eclipse-Juno?
I suppose, you are calling your scripts from a web browser. You need to tell xdebug to actually stop on breakpoints. If you are using Firefox, you can use easyXdebug for that. Make sure to enable remote debug in your xdebug.ini (explained in the extension preferences) and also in eclipse (Windows->Preferences->Php->Debug->PHP Debugger->Config). Then you can enable debug by clicking the little icon in your browser status bar for the next request.
For other browsers there should be Plugins as well, but I haven't used any.