PKP provides access via github to the latest OJS code.
git web interface: http://github.com/pkp/ojs
Read-only git access: git://github.com/pkp/ojs.git
Please consult http://pkp.sfu.ca/wiki/index.php/HOW-TO_check_out_PKP_applications_from_git for instructions on setting up a development environment.
Note that you must rename config.TEMPLATE.inc.php to config.inc.php prior to running the OJS installation script.