1. Launch Portal 2 game disc into the PS3.
2. Hit select on the Portal 2 main menu to launch Steamworks application.
3. Enter current Steam account information, or create a new Steam account.
4. Get on your computer and log into your Steam account. (For new steam users, download Steam and click "sign in via PSN account" when prompted to log in).
5. Click "ADD GAME" in the bottom left and input the unique code that I will be sending.
6. You now have a copy of Portal 2, independent from the PSN account, just like you would purchase through Steam.