Super Mario Galaxy Playable This Year

At his keynote presentation, Miyamoto has revealed that the next-generation Mario game, Super Mario Galaxy, will be playable this year. That does not nessacarily mean the game will be released this year, though. Or maybe it was just bad wording. Nonetheless, how will we be able to play the game? Maybe a demo channel? A video was also shown at the keynote, which will hit hopefully hit the web shortly.