Josh Adell has posted about a bit of automation he set up with Phing and PHP's phar packaging to create an archive as a part of his build system. It's a simple five step process mad even easier by the fact that Phing already has a PharPackage task.
One of the cooler features of PHP 5.3 is the ability to package up a set of PHP class files and scripts into a single archive, known as a PHAR ("PHp ARchive"). [...] I decided to see how easy it would be to wrap up Neo4jPHP in a PHAR for distribution. [...] Since I also started playing with Phing recently, I decided to see if I could incorporate packaging a project as a PHAR into my build system. It turns out, it's pretty easy, given that Phing has a built-in PharPackage task.
He points you towards Phing's PEAR channel to get the tool installed and includes a command-line call to update your php.ini to allow PHP to generate phar files. Code is included to create the phar-generation stub as well as the XML for the Phing build file. You can find his end result here.