Start Portal 2 on Playstation 3 and press SELECT on your controller to bring up the Steam Overlay. It will prompt you to log into PSN if you arenâ€™t already.
Next, it will ask you log into your existing Steam Account, or create a new one if you donâ€™t have one already.
If you choose to create a new Steam Account:
Name of the account will appear to others same as your PSN ID.
You will need to use the same email address used with your PSN ID
Once you do that, this new Steam Account will be automatically linked to your PSN ID.
Next time, when you log into your Steam Account from PC, you will be asked whether to keep these credentials or Not.
If you already have an existing Steam Account:
Log into your Steam account.
It seems existing steam account holders will have several benefits to use their old account instead of creating a new one.
Stats and achievments earned displayed on Steam Profile.
Achievements earned on Portal 2 PS3 will be unlocked on your Steam profile.
Access to PSN and Steam Friends to play co-op games.
Existing friends list will be available to you chat with on Playstation 3 using Steam Overlay.
How To: Access PS3 Portal 2 From PC
Every Portal 2 copy will come with one-time-use-only code that will enable you to access Playstation 3 Portal 2 on PC.
Note. Each code is unique and non-transferrable, and can only be registered to a single Steam account.
Follow these instructions to redeem this code:
After you have linked your Steam account and your PSN ID, log in to Steam on Windows or Mac. If you do not yet have Steam, download the software here.
On your PC, launch the Steam application and log in to your account. If you created a new Steam account using the Steam Overlay on PlayStation3, select â€œFirst time signing into Steamâ€, which will guide you through the first-time Steam login via your PlayStation Network account (you will then be asked if you wish to keep your given account credentials).
Once you have logged in to the account, go to the â€œGamesâ€ menu along the top, choose â€œActivate a Product on Steamâ€, and enter the key provided on the card included in the gameâ€™s packaging.
After this key has been activated, the game can be downloaded and played by selecting â€œLibraryâ€, and then double-clicking on â€œPortal 2â€.