Nintendo announced today that there will be a new version of the DS; it's called the DSi. With so many "improvements" such as a larger screen, a web browser, a music player, internal data storage, two built-in cameras and an SD card slot, maybe that's why they are calling it the DSi.
The DSi will be 12% thinner compared to the DS and the Game Boy Advance cartridge slot will be removed. It will have a 3.25" screen which is slightly larger than the DS screen. Keep in mind that this is measured by one corner going diagonally to another corner.
On top of all these improvements, Nintendo will be opening the "DSi Shop" to sell content over Wi-Fi.
The DSi will be released on November 1 in Japan for the price of 18900 yen which is about $178, and will be available in both white and black colors. Because of strong US sales of the DS Lite, the DSi is not expected to be released in North America until mid-2009.
Source: Joystiq