Steve here - Annette's OH.
Most wireless routers also have some wired Ethernet ports, so depending on the type of the printer, you may be able to connect it directly (or indirectly) to one of those. Once it's on the network, you can print from any PC (wireless or wired) to it.
You said that the printer doesn't have USB - is it a centronics interface (the big old clunky connector)
You can get a device called a print server - I have one from D-Link (
http://www.dlink-intl.com/Products/Printservers/dp100.htm) which allows you to connect Centronics printers to Ethernet. This works really well for us, but can be a bit fiddly to set up. It may be that you would do better buying a printer which actually has an Ethernet port (and make sure that your wireless router also has ethernet ports) so you can connect that way.
Hope that helps. Shout if you need any more!