Attached Link: http://exodus.physics.ucla.edu/appleseed/appleseed.html

http://jedi.ks.uiuc.edu/~johns/raytracer/ There are a few freeware/3rd party apps that will allow you to set up render farms. The link to appleseed even will help you to write your own if you have the backround in programing. Carra does take advantage of dual processors, you can see it render in both #1 & #2 threads if you have a dual sys.