a cross over cable will definately NOT do the job. You can only use a crossover cable between 2 workstations , or one and the printer. I just rethought this... I took you as what you actually wrote, that you want to " network " all three, like an HP with a nic .. Camper is absolutely right if you attach the printer to one of the PC's
what you will need is 3 straight through cat 5 cables and a hub or a switch.
if you are also going to share the internet I would recommend a router instead of a hub or switch, actually a router will not be that much more than a hub or switch, so the router might be better, also has DHCP.