Since late last year the open-source Linux community has been 
ecstatic about the growing progress made by the Nouveau developers. 
Nouveau is an X.Org and FreeDesktop.org project for developing an 
open-source 2D/3D display driver for NVIDIA graphics cards. With NVIDIA 
Corporation not providing hardware specifications, this driver is being 
written through reverse-engineering NVIDIA's binary display driver. 
While the developers of Nouveau are making great strides and this driver 
is taking shape, the open-source ATI driver must not be forgotten.
http://www.phoronix.com/vr.php?view=9730