@Rogue
The drivers are both 2D and 3D.
Actually 2D only are working properly (HW acceleraded).
3D drivers are still very basic.
Here is their status update sentence:
Currently, there is 2D-support, and a very limited 3D support for extremely lucky developers.
More important here is the feature matrix:
http://nouveau.freedesktop.org/wiki/FeatureMatrixCheers
Riccardo