Dumbass networking question

Sunday, May 06, 2007 by Dave Winer.

Okay, here's a dumb question about routers. 

I have four computers plugged into a router via hard wires, and two computers via wifi. All six computers can see each others' shared disks, and life is good.  

I just bought a printer that works over Ethernet. I want to make it visible to all the computers. All the jacks on the router are used up, so I buy another router, unplug one of the computers, plug it and the printer into the new router. However, the only computer that can see the printer is the one that's plugged into the new router. None of the other computers can see the printer. Arrgh! 

Do I need to find a router with more jacks on it, or is there some way to configure things so that all devices plugged into one router can see all the devices plugged into another? 

All the computers are Macs, btw. The original router is a Netgear. I have lots of choices for the new router, the one I'd like to use is a new Airport Extreme that supports 802.11N. 

Thanks in advance for ideas. 

Postscript: The community delivered the answer in record time. Thanks!!