What was once but rumours has now been confirmed. Oblivion will be released for the Playstation 3. The game is apparently a launch title for Sony's next console, meaning the game should be found in stores at or shortly after the release of the console. According to the announcement, the Playstation 3 version will include new content that is not present in the PC/XBox 360 version right now. Also,
Elder Scrolls Travels: Oblivion, which is already available for mobile phones, will be released for the PSP sometime during the Spring of 2007 in both North America and Europe.
Read the full press release here1up.com sheds some light on what this new content for the Playstation 3 version will include. A new faction will be introduced to the game, going by the name of the "Knights of the Nine". The article mentions that the developers described this new faction as "the good Dark Brotherhood".
News story on 1up.com