Backburner is a batch network rendering utility that comes with 3ds Max and Maya. This is used when you want to render multiple images to several computers/nodes.
It has 3 main pieces. Manager, Monitor and Server. The Manager and Monitor are usually installed on the same computer. This is typically your computer that is running 3ds Max, but does not have to be. Some companies have a dedicated Graphics computer that would work well to have this installed on. Also the Server piece needs to be install on the computer nodes. The name Server is a bit misleading, because it infact gets installed on the workstation. A true network server doesn't really have a part in all of this. Also, 3ds Max needs to be installed on the computers with the Server piece. 3ds Max is needed to process the information. It does not need to be registered or licensed. You can install up to 9,999 installations of 3ds Max for the Rendering farm.
So the concept is that you have a 3ds Max model and want to render several shots or an animation. Go thru your regular process in Max that you would normally do to render, but at the end use the Batch Rendering to load your renderings and animations. Then select the checkbox "Net render" button in the lower left and then the "render" button to send the images to be processed. The Manager and Monitor will take over from there. They will pass on the images to the Server nodes for processing.
Here is a great link to Autodesk's website with two videos on Backburner: http://usa.autodesk.com/adsk/servlet/ps/dl/item?siteID=123112&id=14338791&linkID=10381719