Apparently, the game will be launching stateside this summer, with more than 15 characters available from the start. A further two are unlockable (and our money would be on Snake making his second non-Metal Gear Solid appearance of 2008), and there'll be 20 events to keep us distracted and our touchscreens gouged.
Also worth mentioning is the "Voice Boost" feature, which will allow players to bellow into the DS microphone to give their character a performance boost by cheering them on. We saw this idea used (briefly) in Mario & Sonic at the Olympic Games (one could psyche up the crowd by clapping near the microphone), but it seems like it could be a more significant feature here. "The louder you are," declares Konami's press release, "the bigger the boost!" That could get annoying.
[Via press release]