We're not currently planning to open source the platform. But we are encouraging (though not forcing) journals to provide open access to their content. At the moment, our goal is to provide journal editors with a quality tool. We'll be thinking more about open access as we continue to add publishing functionality.

As for open source solutions, there is OJS (http://pkp.sfu.ca/?q=ojs). It's heart is in the right place, but it's an unfortunately clumsy product that lacks many of important features we're looking to add.