LittleBigPlanet Hub is a free-to-play version of MediaMolecule's creative PS3 platformer. The video at Sony's gamescom conference talked about multiplayer, outfits, and the whole creative suite people have some to expect out of LittleBigPlanet. It seems there will also be some content you can purchase.
A PlayStation Blog post details LittleBigPlanet Hub. All content from the first two games will be available to purchase in Hub. If you own them, you can fully import your profile to Hub, which will be getting exclusive new content, starting with a new level. Hub affords full, free access to 16 LBP and LBP2 levels. The Create Mode is also available, unrestricted, while it seems like you'll only be able to play staff-selected community creations.
LittleBigPlanet really started the culture of sharing and user-generated content at Sony, a culture that trickled into things like inFamous 2. Having a free-to-play version of LittleBigPlanet is a nice way to promote longevity of the PS3 and give a really neat tool/game to a lot of people -- I'm thinking young kids in particular -- that aren't on the cutting edge of "next gen."
Plus Sackboy is so cute.