Since it is somewhat related, I recently found VisualHub handy for the Mac for encoding multiple files. If you have multiple Macs on the network running 10.3.9 or 10.4, they can all help on the video encoding by simply turning on the XGrid option in the sharing system preferences panel. VisualHub will then use that to distribute tasks out, with no extra software install necessary on the other machines.

The downside to it is that it only does single threaded encoding, so if you only have one file to encode, only one CPU will be used.