No it's not to make sound hip like the iPhone, iPod or iMusic (surely). So is it Internet, Input, Important or Incredible?
The "i" is symbolic of the subject "I" and its personal aspect. Plus, the addition of two cameras gives the system its own "eye" on things. Nintendo hope that the Nintendo DSi becomes more than a game system and more of a personal tool to enrich our daily lives.
Nintendo of America representative
Some Nintendo DSi games