Game's officialy out in Japanese arcades a little later this month (and will also be at San Diego's Comic Con and Evolution 2008), but 1up has some kind of cutscene from the game on their site.

GameVideos.com - Street Fighter IV 'Akuma vs. Ryu' Video

I had heard about them using animated cutscenes for different things, though I have no clue where this would fit in to the game.

The thing at the end was pretty exciting for me. He punched a waterfall!