Weekly Geekly

Ghostwire for DSi is an adventure game which uses the DSi's camera to overlay a view of the astral plane on the real world, creating an augmented reality gaming experience.

Your portable device is used as a portal to the astral plane, and helps you find and collect ghosts that exist all around you. In your quest you use real tools, such as the built-in camera and microphone, as well as abstract ones like an "EMF tuner" for tracking down the ghosts.
Once you find the spirits, you document them and find out why they haunt our world. They also give you riddles to solve. Ultimately, you will help them find peace.

This looks to be one of the first games to make good use of the new features found in the DSi, that will help differentiate it from what the PSP has to offer. However, with almost all mobile phones now touting a camera, you can probably expect to see Ghostwire released on a variety of platforms.

Check out the DSi trailer below:

Thanks to @stanto for the heads up