Media Molecule's LittleBigPlanet has scored itself a comfortable G rating from the Classification Board. The advisory notes that the "gaming experience may change online". Given the level of customisation in the PS3 title, you'd hope it would!
In a related note, Call of Duty: World at War bagged an MA15+ on the 22nd, with the advisories of strong violence, language and "may change online". Also note the "Activision Blizzard" moniker is out in force.
LITTLE BIG PLANET Game (Playstation 3) [Classification Board, thanks Simon]