What kind of connection does the printer provide, if USB you can use a USB hub, if RJ45, use a switch. Printer needs to have network support to use a switch.
If you only have two computers, you can set up a "peer-to-peer" network using a crossover cable connected to your ethernet connections. Check out this site for details. If you want to hook up 3 or more, you will need a hub.
Do you want to share the printer connected to another computer? Or do you want to connect two computer to the printer? Which one? You don't need Internet to share a printer.