If you're hoping to learn more about the device which you'll soon be hiding within your deepest, darkest pocket, filling you with terror that, while withdrawing your keys, you'll accidentally expose the accessory, bringing your reticent Pokémaniacal tendencies to light, forcing you to ... wait, what were we talking about again? Oh, yes, the Pokéwalker accessory which comes with HeartGold and SoulSilver was recently demoed in a video released at the Nintendo Media Summit, and posted above. Looks like it has some neat functionality beyond just step-counting.
Oh, the games themselves also received their own trailer, which is posted after the jump. We've seen most of the footage shown there before -- though the music is new, and totally triumphant.