iPhone 2.0 Japanese Keyboard Video
The demo appears to be running within the iPhone SDK simulator. We've previously posted screenshots of the iPhone 2.0 Japanese keyboards. Tokyo Mango describes the input method:
You can pick from a muti-tab style kana keyboard or a sliding keyboard. Japanese kana letters are organized in groups of five according to a beginning letter and corresponding vowels (a i u e o), so you can either put in the first letter and then hit the same key b/w 1-5 times to get the right sound, or you can put the first letter in and then scroll through to see all five sounds and pick the right one.