Router and Their Limit?
 

I have an SMC Barricade and it says it can support 255 computers. It's wireless, but only has 4 ports on it. Does that mean it can support the 4 and then 251 wireless computers? I would much rather have the computers wired, so is there a way to daisy chain another router or something to get them all working?

Technically your router can hand out 253 IPs through its DHCP server, whether it be through wireless or ethernet, it doesn't matter. You can buy a switch and plug in into your router, most routers/switches these days should have auto-sensing ports so you may not need to worry about the following but just as an FYI. To use a standard ethernet cable, the switch will need to have a uplink port if it doesn't have auto-sensing ports or if it doesn't have a uplink port you will need a cross-over cable to connect the two devices together.

So two routers wouldn't help me at all?

Lets take a step back for a sec and answer what is a router. Lets stick to Cable/DSL routers in this case. These type of hardware devices route internet bound packets from your internal (private) LAN to the outside WAN (your ISP).

So how would this help you? Short answer, it won't, as mentioned above you need to connect a switch to one of the four ethernet ports on your router.

I know what a router is. I don't know what a switch is. I have a few routers, and what I was using them, the WAN went to the modem and the computers plugged into the ports. I was kinda hoping that if I plugged in all the computers in the ports, then plugged the WAN from the one router into the port of another, it would let me connect multiple routers. Kind of like each router has 4 inputs and 1 output. Then I just make the 1 ouput be an input on the other router.

It may work that way but its not proper, switches are very inexpensive these days. There's two problems I see with that configuration.
1. DHCP scopes being the same, which can cause conflicts.
2. Not having the ability to access computers behind the second router.

Here's a solution if you really don't want to buy a switch, kind of goofy in my opinion since you would only be gaining three ports but you don't have to hook it up to the WAN port on the second router. Hook up the second router by itself first, login to the web interface and disable DHCP and the WAN port if possible, then you can connect the two routers together without having to worry about IP conflicts through the LAN ports.

I'll try that first before thinking about a router. Would I connect the two by having the port of one go to the port of the other, would I still use the WAN as the output and a port of the other as the input?

You would be going from a LAN port on the first router to a LAN port on the second router, you won't be using the WAN port. If it doesn't work you and you still want to do it this way you will need a cross-over cable. I'm pretty sure the newer Linksys routers will auto detect this type of connection but I'm not sure about other manufacturers.

If you have that many devices on one router couldn't that slow down the connection for everything and increase pings accross the network even?

If you were to hook up 253 devices of course it would cause a lot of networking congestion resulting in high latency. Now as for connecting a few Ethernet devices together to make a bigger network, no.