Gamers can stream the conference on their 3DS.
Yesterday's Nintendo Direct event is streamable in its entirety on the eShop in Japan. The Japanese version runs a little bit shorter than the English language version (about a minute shorter), possibly due to the lack of explanation of the kanji for dokusō (meaning “creating something unique”) and the fact that President Satoru Iwata speaks Japanese faster than he does English.
UPDATE: The Nintendo Direct event video is now available on the eShop in territories outside of Japan. E3 game video downloads are promised.