While this ctx_voodoo installation really only affects those wishing to play with this staging driver early as Red Hat ships Fedora with ctx_voodoo and other distributions will likely do the same (or at least make for an easy installation), there is a better solution on the horizon and it will make this free software driver even more pure.
Red Hat's Ben Skeggs over the past few days ended up being able to write his own firmware replacement for the context switching microcode (ctx_voodoo) that for at least his GeForce 6/7 graphics cards is working correctly. His free software version of ctx_voodoo is much less complex than NVIDIA's blob, but for the Nouveau purposes it seems that it will work out at least for the time being.
This generated firmware made by Ben can be found on the Nouveau mailing list. Assuming others report success with this firmware, it will end up being pushed into the DRM shortly, which means the NVIDIA ctx_voodoo right now will only be needed for the GeForce 8 series graphics cards and newer. Over time we may end up seeing new firmware replacements for the other NVIDIA graphics cards too.