Important note.
There are 2 main types of router, one for ADSL lines (normal phone lines) and the other for Cable (Virgin, NTL, Telewest etc)
Make sure you buy the correct one.
Also there are WIRED routers, where you can only connect to the router via a wire, or a WIRLESS router, where you can connect to the router EITHER by wireless or wired.
Some ROUTERS do have a printer port so you can connect your printer to the router as though it was a network device and print to it from each PC.
Some PRINTERS (usually laser) do have a network card built in (Network ready) so you can plug it straight into the router.
Welcome to the world of networking !