Pok?on Box is a game that allows players that own copies of Pok?on Ruby and Sapphire, and eventually perhaps Pok?on Fire Red and Leaf Green, to store Pok?on onto a Gamecube memory card. However unconfirmed, it is said that players will be able to store up to 1,500 Pok?on onto a memory card.
The only other known feature for Pok?on Box is being able to play the Pok?on Ruby and Sapphire games on the television. This is a feature confirmed on http://www.pokemon.com.