That's right folks, it has now been confirmed that PC and PS3 will have exclusive co-op cross-platforming through steamworks on the PS3. It will include auto-updates, downloadable content, and community support, like the PC version of Steam, but skimmed down. It will also include the SteamCloud, which will allow PS3 users to have their data saved on steam servers, in case of malfunctions or loss of saves.
What comes with the PS3 version, is both the PS3 disc, and a digital copy of the PC version, which can be tagged onto a Steam account. The Steam account must be linked with the PSN account however, but nonetheless, it means you can easily play one or the other in different scenarios.
This is just ground breaking news, and the first, of what is hopefully the start, of a new era in cross-platforming.
official press release
Promoted forum item