Ars Technica has some details they think are fairly reliable about the OS the PS3 will be using
. From the article: "In fact, there was some question as to what such an OS would be doing with all that leftover horsepower. I think the answer is probably to be found in the interactive, real-time, user- and network-facing sides of the console's functionality. This includes not only the audio/video chat and IM referenced in the PS3 Portal rumor, but also the aforementioned DRM (for streaming and downloadable online content that might be dynamically integrated into the game experience) and security/privacy-related code. "