Hi does anyone know the system requirements on the computers in the network when network rendering? Do I need OSX on all machines or can I use older macs?

Personally I use an old P IV 1 G with a new P IV 2.8 G. It works fine. The older machines may render slower, but that's not important:-)

It so happens that I got access to 4 old power PC 7100/61/AV for free! You think it will work? What OS does it take to install rendercow?

According to the back of the Mover 4 box, RenderCow requires OS X and a G-3 class processor. On a Windows setup, it says P-3 class processor and anything from Win95 on up. As for working or not...It never hurts to give it a try! One thing you might want to do is have a piece of paper handy; there may be a file or files not in the OS install that RenderCow needs (I've gotten in the habit of just installing Visual C++ 6 on all my windows boxes, as that seems to include about a dozen dll's that various things need. It avoids having to gouch at the MS site with a 'non-standard' browser (I use Opera, and yank out Exploder every chance I get), and installing a lot of garbage I don't need. And I get this nifty debugger for any problem children... :P ). If it installs and runs on startup, you're in business. You might want to give each of the boxes an easy to remember name; if HyperVue doesn't detect it, then you can add the extra node by name.