In Mac OS X 10.9, apache, php and xdebug are already installed. To activate and configure them (and to install MySQL), follow this guide: Get Apache, MySQL, PHP and phpMyAdmin working on OSX 10.9 Mavericks

For Xdebug, add this at the end of the php.ini file (sudo vi pathtoyourphp.ini) (in vi, press "G" to go at the end):

[Xdebug]
zend_extension=/usr/lib/php/extensions/no-debug-non-zts-20100525/xdebug.so
xdebug.remote_enable=1
xdebug.remote_host=localhost
xdebug.remote_port=9000

Check also: Configuring Xdebug in PhpStorm

Check this webinar: Debugging PHP with PhpStorm (or directly this YouTube video)

Remember that you have to manually start apache:

sudo apachectl start
sudo apachectl stop
sudo apachectl restart

To start/stop MySQL, if you followed the initial guide, you already know that you can find a MySQL icon in your System Preferences.