a stand-alone print server option is the best, but it;s not worth it if there are only 2 computers in the "network", this option requires the existence of a network, which means network adapters for the PCs, a print server, and a hub (switch is preferable, router is not meant to do this) not to mention the cables you need.
if you setup a 2 pc network, you can forgo the hub, and use a crossover cable, which directly connects 2 PCs ONLY in a small network. once the network is properly set up (workgroups etc) you can share the printer. the computer that the printer is directly connected to is taking the role of being a print server (as opposed to being stand-alone) and has to be on at all times the other PC requires something printed. here only the network adapters, and a crossover cable is needed. as well as the electricity...
there is another option, you can get a usb switch, this is a little box with a switch that changes what computer the printer is connected to... the switch is either a physical switch you click, or an electronic one that is "smart".. you will need extra cables for this as well... there is also a parallel port option for those printers that use the parallel port
summary:
1st paragraph: standalone print server is the best option, needs time to set up, NO maintenance, expensive
2nd paragraph: PC as the print server, cheapest, needs less time to set up, minor maintenance since the PC has to be on
3rd paragraph: usb switch, cheap, no time to set up, high maintenance to minor maintenance depending on the switch
ALSO:
some printers have USB and parallel port, the printer may be able to be shared if one PC uses the usb, and the other uses the parallel port. this requires only ONE pc to print to the server at any time. and this may not work at all, but is worth investigating since it's cheaper than those more sophisticated options. (cost = buying a cable)
ps:
once you have made up your mind, if it involves networking, and you need help, go to the networking forum to ask questions, continuing this thread wont help =)