Does 2D rendering work?
Officially: No.
Unofficially, 2D works mostly as well as the nv driver.
If you have a PCI-e card then it will be very slow rendering, even compared to nv due to the slow video to system memory copies. This will be fixed as soon as the TTM memory manager is integrated into XOrg. This will happen quite soon.
Until then, speed up 2D rendering by an order of magnitude, by using *Option "MigrationHeuristic" "greedy"* in the Device section of xorg.conf
Does 3D rendering work?
Officially: No.
Unofficially, 3D might work depending on your card type and lots of other things. At the moment the rawhide [http://dri.freedesktop.org/wiki/DRI dri] (mesa) is version 6.5.2. This means the nouveau_dri module is not installed and so no 3D operations will be accelerated.
If you install a mesa snapshot from [http://people.freedesktop.org/~hughsient/fedora/utopia.repo here], some simple 3D applications will be working, for instance glxgears works at about 300fps.
[http://people.freedesktop.org/~hughsient/temp/nouveau-dri-2-small.png]
For some cards, a [http://dri.freedesktop.org/wiki/DRM DRM] snapshot will be required (a kernel rebuild). Fedora already patches in some nouveau drm functionality into the kernel SRPM, but it is not updated frequently.
Texture mapping will also not work (requries TTM), so don't expect you can run any OpenGL games just yet.