The most recent edition of Game Informer Australia magazine is claiming that Sony has told them that developers are preparing games for the currently unanounced Playstation 4.
The existence of the Playstation 4 has been predicted by many gaming-industry analysts, and is said to be releasing in 2012. This is no means a direct announcement of the new device, but it is an indication that Sony is preparing its publishing partners for the release. As a standard game can take anywhere between 2-4 years to be properly developed, it is necessary for developers to know the specifications for a new console well before the public finds out about it.
A development cycle for the launch games can be as little as two years, this is pointing towards a 2012 release for the console. As the Playstation 3 will be at a grand old age of 6 at this time, it is not unlikely that this will be the year the console launches. So this claim by Game Informer may be true, giving us an even greater indication that Sony is actively pursuing the follow up to the Playstation 3. It is more than likely just developers being given information about the possible specification for the device, allowing them an opportunity to properly develop games for the device well before the actual console is announced.
Source: Game Informer Australia Issue #9
The snippet (seen above) is part of the magazines 'Bite Size' segment, which is the location for all the news that has happened in the past month. This is a news section for the magazine, not a rumor section, so the information is possible.
It is a not very likely at all that Sony will announce the successor to the Playstation 3 anytime this year, but an announcement next year is increasingly being true as more and more rumors come to light, only time will tell.