phpAr is a simple PHP class to let you unarchive .ar files.
$archive = new phpAr(/* Name of your file */);
This is how to load a file.
$archive->listfiles();
This will return an array with all the files inside the archive. If no files were found, will return false.
$archive->getfile(/* File that you want to extract (string) */);
This will return an object with a the informations and the content of the specified file. If phpAr can't find the file, will return false.
phpAr is released under CeCILL-C license.