Network a Projector

You would need a driver of some sort.

What brand and model of projector are they?

The brand and model is going to be critical here.

Typically network projectors work by software running on a computer streaming a video stream of the screen display over the network. There are several methods of doing this. Some are based on Microsoft's Network Display protocol, others use proprietary software.

Either way you'd need something running on the computer that gets it to output the video stream. I know Epson, for one, have a Mac client for their network video products (and it works pretty well). Other projector vendors may do, too, but you'll need to check with the specific manufacturer.

This would be the page you're looking for. Note, though, that they don't mention Snow Leopard support, so it may or may not work.