The DSi will be available in both white and black versions and will include two cameras, a bigger screen, a DS-specific download service, an SD card slot, and music playback functions.
The new DSi screen will be 3.25 inches diagonal width, 0.25 inches bigger than that of the DS Lite. It will also be thinner than the DS Lite, measuring 137 millimeters x 74.9mm x 18.9mm, in comparison to 133mm x 73.9mm x 21.5m and will also be 4 grams lighter.
Hardware improvements include a better battery recharge time, on-board memory and an SD card slot.
Users will also be able to use a new online download service featuring DSi points, similar to Wii ware, that will allow us to download full games.
Other features include:
Built-in web browser
Backwards compatibility with the DS Lite (no Gameboy advance games though)
DS and Wii compatibility, which will allow you to take pictures with your DS and play them on your TV via Wii.
In the list of specifications, there does appear to be a backwards step for the handheld - the battery life. With the DSi, battery life will be shortened from 15-19 hours of play at minimum level of LCD brightness and 5-8 at full brightness (DS Lite specs), to 8-15 and 3-4 hours respectively.
The full specs can be found at the official site, however, if you can't speak Japanese you're stuffed. Alternatively, head over to IGN , who have kindly translated it.