Has the beta access changed for this? Do I just need access to the normal Unity3D beta(which I have) with PSM tools installed or something more? I would like to start making plugins for PSM...
Unity-for-PSM is released as a 'Public Preview'. Though it's similar to an "open beta", it does not use the "normal Unity3D beta" program. Please have a look at the 'sticky' Sony PSM Development thread, where we posted links to all the necessary components.