for all who want to have a full open source renderfarm, I want to mention the render queue DrQueue, which is surely known to some of you, together with the new webinterface DrQueueOnRails. Add some Linux distribution and Blender to it and you have a pure free and open source render pipeline.
The webinterface also supports rendering with the commercial renderer MentalRay (for 3DSMax, Maya, ImageStudio, SolidWorks).
More information can be found at http://drqueue.org/project/wiki/DrQueueOnRails
If you are interested, please try it out. I will try to give you some help.