Can I make two wireless routers communicate using the wireless?

"There are a lot of good ideas in the answers here. I'm going to compile them into a meta-answer and indicate what I did.

What I was looking for was a wireless bridge. In this configuration, two wireless routers communicate via their wireless connection and the remote router can make its wired ports available to nearby computers.

You can set this up in one of two ways.

1) Buy two routers which support bridging. You will probably have a much easier time getting them to talk to each other if they are from the same manufacturer.

2) Install replacement firmware in your router which supports bridging. Obviously, you do this at your own risk. The procedures do not appear that difficult but you can brick your router if you mess up. The firmware that got the most mentions here is DD-WRT. Be SURE to check that your router is on the list of supported hardware before making a purchase and be especially sure to pay attention to version numbers.

I went with the first option, mainly because I did not want to invest $150-200 on good wireless routers and then risk bricking them. If I had access to some cheap, supported wireless routers I DEFINITELY would have screwed around with the second option.

Here is what I did:

I bought two NETGEAR WPN824 wireless routers for $60 each (Best Buy had them on sale). Only WPN824v3 supports bridging which is sad because my current router is a WPN824v2. Once you get them past the initial setup (the install CD is a big waste of time, by the way), setting up a bridge is easy. You just check a box on the web configuration page and enter the mac address of the other end. The only thing I wasn't happy with is that the router can only support WEP in bridging mode which kind of sucks. So it turns out that I'll be keeping my old router around since WPA is more secure and I really don't want to go around to the myriad network-aware devices in my home and reconfigure them. Note that you CAN run a wireless bridge AND access the wireless normally with the WPN824, I just chose not to do so. So now I'm all set - I have wireless throughout my home and I have four available wired ports in my office, all for the low cost of $120. The WPN824 supports a couple of repeater points so you can buy another one if you need some wired connections elsewhere in your home or business.

The final chain is:

[cable modem] <-cable-> [original non-bridged router] <-cable-> [new router, bridge base] <-wireless-> [new router, bridge repeater] <-cables-> [PCs in office]"

"I'm pretty sure this can work with special router firmware

for example, DD-WRT (custom firmware for some linksys routers) can be set up to run as a repeater. The linked tutorial does not mention any cabled connections. But I'd imagine you could plug an Ethernet cable into the port and it would work as expected.

Ah, looks like there's an entire section in their documentation for linking routers"

If the routers you had were compatible, some models support "bridge" mode which you can bridge each node together. However, you would not have any wireless device connectivity because the wireless communications would be dedicated to the "bridge".

What you need is a wireless bridge/access point like this dlink 1522 although updating the firmware on a router seems fun if you have one that would work.

"You are not going to have much luck trying to get one access point to associate wirelessly with another. Some higher end wireless routers have support for dual radio setups where the users talk to the network in the G or N band and it talks to the back end network using the wireless A band.

With the higher end wireless routers it allows you to network all of the access points together into a single network. Getting the routing to work will be a bit challenging as well.

Lower end wireless routers generally would require a direct Ethernet cable between devices for it to work properly."