membership network of websites

i have a network of websites that im making but i would like them all to use the same memberships like if on the forums they have premium then on the adult website they have premium too is their anyway to do this ?

your going to need to build a framework and have API's accessible. this way you can have a master site that holds the member's info and the rest just pull it when needed. the issue from this is when you bill the client they have to know who company XYZ is if not you could end up worth charge back issues. No matter how you look at it you will need payment APIs (on top of the payment gateway your will be using) and member look-up APIs as well.