"Pokemon Mystery Dungeon: Gates to Infinity" for 3DS won't hit store shelves until March 24th in North America, but Nintendo has revealed that DLC will be available on launch day, and the first pack will cost you a whopping zero dollars.
The DLC gives players new Mystery Dungeons to explore, which in turn provide new items to collect and new Pokémon to interact with. The first downloadable goodie is the Poké Forest Mystery Dungeon, which will be free from launch day through April 30th. There will also be three other Mystery Dungeons available on day one and additional content released throughout April. That you'll have to pay for, but Nintendo hasn't revealed pricing just yet.
Nintendo has also revealed more info on multiplayer. Up to four players can connect wirelessly in Companion Mode, working together to explore dungeons and collect experience and items that carry over to your single player adventures. You can also revive other players' fallen Pokemon by tagging them using StreetPass.