In a not-so-shocking move, Nintendo has announced that their new handheld console is set for release by March 2011.
This new console is, perhaps tentatively, called the "3DS", and, as the name would imply, allows for 3D effects in gaming, supposedly without the need of 3D glasses!
Any other information is scarce, other than being backwards compatible with DS/DSi games, but you can bet your Wii that Nintendo will reveal more this Summer at E3.
More, rumored info:
* Larger twin screens closer in proximity
* High-powered, like a GameCube, with nVidia Tegra
* Built-in accelerometer, akin to iPhone/iPod Touch
* Utilizes carts like a DS
Keep in mind that not all of these are all 100% confirmed, but likely.