IGN posted some details on the new features:
"Select DSi Camera from the menu, and you'll quickly transform your system into a digital camera. Pics that you've taken can be transferred via SD card to your PC and cell phone. You can also send snaps between two DSi systems wirelessly.
In typical Nintendo fashion, the camera will include some game elements. Among the fun features are a facial blending tool, a method for changing facial expressions, and a means of measuring similarity between two faces. The camera itself can be set to take pics in a variety of modes, including normal mode, "trick" mode, and frame mode.
Select the DSi Sound option from the menu, and you'll have yourself a mini music player, complete with a variety of visualizers and audio tools. The system can remove vocals, allowing you to sing along for yourself. Nintendo also appears to have included a built in Band Bros. of sorts, as you can tap buttons along with the rhythm in order to overlay sounds. You can also record 10 second audio samples through the system's microphone for use in your music sessions.
Unfortunately, those looking for MP3 support are out of luck. The DSi Sound program will only support AAC format.
Finally, there's the DSi Shop, a program that serves as the DS version of the Wii Shopping Channel. You'll be able to download free and paid programs from this under the "Nintendo DSiWare" label. Two free programs have been mentioned by Nintendo, an internet browser and a digital notebook that lets you create moving comics."