Unfortunately, we're starting Monday morning off with some slightly disheartening news. It has been revealed by the LittleBigPlanet community manager on the official US forums that four-player online co-op in the Create will not be available at the launch of the game. Instead it will be added in the "first major update after the game is released. Obviously there's no indication of when we'll be seeing that first update, but apparently Media Molecule is now hard at work on post-launch content, with emphasis squarely on four-player online creation.
You'll still be able to create levels with three of your buddies at launch, they just have to be in the same room as you. Four-player online co-op will obviously be available out of the box too. There's still plenty to do (and be excited for) in the game, which should keep us busy until Media Molecule release the online Create patch.