Pokémon Ranch, is that you can import critters from Diamond and Pearl. According to the latest preview from Famitsu, you'll be able to play with those Pokemans once they get to the ranch, in the game now officially titled Minna no Pokémon Bokujou (Everyone's Pokémon Ranch). No better way to give your fighting slave a break than by forcing it to dance and give you a piggyback ride!
You can also pose (your Mii) for pictures with those Pokemans, which can be saved on an SD card and transferred to a computer. A real computer, not one of those in-game Pokémon computers used to transfer captured Pokémon.