Network Rendering Farm?

[erstwhile]

Hi.
I'm interested in setting up some kind of system that would let me render on multiple computers over the internet.  Except for Mandelbulber having a "net render" mode I don't know where to start researching so I'm interested to know what other software (fractal software or other rendering software) lets you split your rendering in a virtual rendering farm.
Thanks.

[lkmitch]

Ultra Fractal supports rendering across multiple machines.