REQUIREMENTS:

Add your users to the "video" group to be able to use the nvidia
devices required for 3d to function properly.

PRECAUTION:

PRE-INSTALL:

POST-INSTALL

Use opt/gl-select from ports to select the correct gl/glx libraries 
and extensions like so:

   # gl-select nvidia

PRE-REMOVE:

POST-REMOVE

Use opt/gl-select from ports to revert to the xorg gl/glx
libraries and extensions like so:

   # gl-select xorg


When UPGRADING/DOWNGRADING the nvidia port (where the version changes),
use gl-select to revert to xorg and then re-select nvidia in order to
refresh the libGLcore and libGL symlinks, like so:

   # prt-get update nvidia-legacy-71xx
   # gl-select xorg
   # gl-select nvidia

NOTES:

The following GPUs are no longer supported in the regular NVIDIA
Unified UNIX Graphics Driver. Instead, these GPUs will continue to be
supported through special "Legacy GPU" drivers that will be updated 
periodically to add support for new versions of Linux system 
components (e.g., new Linux kernels, new versions of the X server, 
etc).

There are presently two Legacy GPU driver series. The 1.0-71xx series
supports TNT, TNT2, GeForce 256, and GeForce2 GPUs. The 1.0-96xx 
series supports GeForce2 MX, GeForce3, GeForce4, and Quadro4 GPUs. 
For a complete list of the GPUs supported in each of the Legacy GPU 
driver series, see the lists below.

The 1.0-71xx driver supports the following set of GPUs:
NVIDIA chip name                 Device PCI ID
RIVA TNT                         0x0020
RIVA TNT2/TNT2 Pro               0x0028
RIVA TNT2 Ultra                  0x0029
Vanta/Vanta LT                   0x002C
RIVA TNT2 Model 64/Model 64 Pros 0x002D
Aladdin TNT2                     0x00A0
GeForce 256                      0x0100
GeForce DDR                      0x0101
Quadro                           0x0103
GeForce2 GTS/GeForce2 Pro        0x0150
GeForce2 Ti                      0x0151
GeForce2 Ultra                   0x0152
Quadro2 Pro                      0x0153

Referenced from: http://www.nvidia.com/object/IO_32667.html