Of course, Portal 2 on PS3 will offer cross-platform matchmaking with Steam friends, Steam achievements (in addition to PS3 trophies), and Steam Cloud support to save co-op and single-player game progress on PS3. Note: "Game saves and progress from a PlayStation 3 are incompatible with other platforms."
To access all these features, Portal 2 on PS3 will feature the familiar Steam overlay, giving players a quick way to access "both PSN and Steam friends," for text chats (and we presume voice chats), profiles, friend requests, and game invites. In order to access all these Steam-y features, you'll need to link your PSN account with your Steam account. Don't have a Steam account? You can make one "with the click of a button," Valve promises. And if you're wondering how that "free" Steam Play version on Mac or PC will work, Valve says, "linked players of the PS3 version of Portal 2 can also access and play their copy of Portal 2 on any PC or Mac by redeeming an in-box access code on their computer."
If this works as well as we think it will, we don't think we're alone in suggesting that all games ever should do this. Check out the associated Steam support page for plenty more in the way of details (and even some pics).
Valve's Highly-Anticipated Title Prepares for Launch On PS3
April 13, 2011 - Valve, creator of best-selling game franchises (such as Half-Life, Portal, Left 4 Dead, and Counter-Strike) and leading technologies (such as Steam and Source), today disclosed details regarding the Steam experience designed for the PlayStation®3, which is set to debut next week with the release of Portal 2.
The first title to support Steam on a console, Portal 2 offers cross-platform matchmaking, gameplay, friends, chat, and achievements, all powered by Steam. Steam on the PS3 also saves co-op game progress and single player saved games to the Steam Cloud, enabling players to pick up where they left off on any PlayStation®3.
The Steam overlay for PS3 provides access to both PSN and Steam friends, displaying their in-game or online status and providing a quick pathway to text chats, player profiles, friend requests, and game invites. Steam Achievements are earned in lockstep with PSN Trophies and are also accessible within the Steam overlay.
Steam on the PS3 provides access to all of these features once the player has linked their PlayStation® Network account with a Steam account, which is done right within the game. A Steam user can login to an existing account, and anyone new to Steam can create an account with the click of a button.
In the spirit of Steam Play, linked players of the PS3 version of Portal 2 can also access and play their copy of Portal 2 on any PC or Mac by redeeming an in-box access code on their computer. The Steam client verifies the linked customer and then lists Portal 2 among their library of Steam games for PC and Mac.