Today while I Am searching for a simple solution to create .phar files google tooks me to a project called Box by Pádraic Brady on Github. The Box application simplifies the PHAR building process and helps to create .phar file from php project.
.phar files are similar in concept to Java JAR archives, but are tailored to the needs and to the flexibility of PHP applications. A Phar archive is used to distribute a complete PHP application or library in a single file. A Phar archive application is used exactly like any other PHP application.
One of the most famous application that is used .phar technique is compser which is tool for dependency management in PHP and published as .phar file which can be executed from the command line (cli).
If you don't have any information about .phar files take a look to PHAR file format at wikipedia or google it!.