Both Uncharted and Resistance will allow you to explore empty levels from the game as your Home avatar (hopefully, with your friends - that would make it extra cool). Resistance will also have a game-space in which we'll be able to explore unseen areas of the game as well as listen to extra content from the game in the form of "intercepted radio transmissions" which will expand on the storyline.
Uncharted is pegged to have a Contra-style 2D side-scrolling shooter based on the game, available in its gamespace. Warhawk, on the other hand, will feature full game launching from within Home and a "war room" which will allow players to draw out battle plans on a virtual sandbox map of the level. If this all comes true, then Home will be even better than we ever imagined. Sony is apparently using these games to show third parties and other developers the potential of the service. Let's keep our fingers crossed that this will all come true.
Read - "How Resistance: Fall of Man makes Home really, really cool" @ Kotaku
Read - "How Uncharted: Drake's Fortune makes Home really, really cool" @ Kotaku
Read - "How Warhawk makes Home really, really cool" @ Kotaku