https://github.com/kbjr/Git.php
Git.php is a wrapper class around git calls that uses proc_open instead of exec to run the commands. While it does not have push/pull methods, it does have a general run method for running custom git commands, so it could be used something like this:
$repo = Git::open('/path/to/repo');
$repo->run('push origin master');
It also does have methods for cloning (clone_to and clone_from which do local cloning and clone_remote for remote cloning).
