Kyle Schubel, senior producer at SCEA, has revealed that there will be a LittleBigPlanet closed BETA this summer. Schlubed confirmed that the game will "1 to 4 Players on 1 to 4 PS3s" which means "up to 4 player online and offline."
Schubel also said the game should see a full release in September or October.
To quote: Schubel confirmed the excellent multiplayer support - the game will support 1 to 4 players on 1 to 4 PS3s. That means up to 4 player online and offline. On the DLC side, there will be capacity for 1 million user-created levels on a planet, and the number of planets can be expanded.
And to filter through the inevitable mediocre (read: rubbish) levels, you'll be able to search by popularity, upload date, what your friends have been playing, other levels created by a user and ratings. Video below!