Again from IGN: "Monster Rancher DS (or, as its called in Japan, Monster Farm DS) is a simulation game where players create and raise their own monsters, then face them off against CPU and human-controlled opponents. Tecmo is using putting the DS to full use, primarily in how you go about creating your new friends. You can use the stylus to draw patterns, which are then converted into monsters. You can shout thing into the microphone to create another set of monsters. Or, if you still have Game Boy Advance carts about, these can be inserted into the Game Boy Advance cartridge slot for even more monsters; this takes the place of the CDs that were used to generate monsters in previous Monster Rancher games. Once you've created a monster, you have a number of ways to train it. New to the DS version is a board game which you can play to raise your monster. Alternatively, you can select training options the old fashioned way, from a menu. Eventually, you'll be able to merge multiple monsters into a super monster and beign climbing the ranks of a monster tournament. This first DS entry in the Monster Rancher series will feature Wi-Fi Connection compatibility. We presume this means you'll be able to challenge far-off friends to monster duels. Monster Rancher hits the Japanese DS on 7/12. A US release has yet to be announced." What would be better than having GBA cartridges to replace a CD, is if this game came with a GBA cart that had a USB lead attached so you can connect to a device to transfer MP3's so you could get monsters from them.