Ok I have 2 Linksys WRT54G broadband routers and a ADSL Modem.
I have one connected to a ADSL modem acting as a bridge with PPPoE configured on the router.
Now I want to connect another identical (well it's a lot newer) Linksys.
I can and should do this with the WAN port right?
Shouldn't I connect the WAN port of my new (the one I want to add to the network) to a LAN port on my old (the one that is connected to the modem) router?

The reason for all this it that I'm playing with Linux on the WRT54G
here a link if youre interrested Linux on WRT54G
I bought one more only for this

And the router's WAN port MUST be configured to be able to send over the linux system to it.

It would also be good if I could connect computers to the new router and they could access the Internet AND the other computers on the old router.

I have tried to find a tutorial or guide with google to help me, but I haven't found so much, and those I found didn't work sadly.

Some things I have read though was that I should disable DHCP on the new router.
This should be right because I have read it on a lot of places.
What I have a problem with is how the wan port should be configured.
first should it be DHCP or Static? my guess is Static.
then what IP address should the WAN port have?
and what gateway?
and the hardest of them all netmask!!!?

I have read that the gateway should be 0.0.0.0 or whatever is that right?

also what should the netmask of the network be, the LAN ports.

should any of the ports or netmasks on the new (slave router) be the same as the the old router (master router)

I shouldn't have to change anything on the old router right?

can the ip addresses of the routers be like; Old 192.168.1.1 and New 192.168.1.2?

I will be very happy if someone can help me by either pointing me to a tutorial or finding a solution.

here how I want it to be configured
modem-1 to router-1
cpu-x to router-1
router-2 to router-1
cpu-x to router-2
hope you understand

Let's take this one step at a time.

1) Where do you want to connect the 2nd router? to the first?
Yes = Your WAN configuration should be just like any other computer connecting to that
router. i.e If you were connecting computer A to the first router and had a setup
of ip=192.168.1.2;Subnet=255.255.255.0;Gateway=192.168.0.1. THAT
would be your WAN configuration.
No = If your connecting it directly to the DSL, configure it as you would a computer (like
in 'Yes').
2) If you want to run DHCP on the new router, feel free AS LONG AS: you connect the
other computers to the LAN side of the new router. That shouldn't interfere with
anything seeing as how your router is dividing your network. I don't know who told you
that, but, in reality, the internet works on this exact concept. So, it's up to you. If
you want to run DHCP, just ensure that you are connecting to the WAN port and not a
LAN to LAN port. If you connect from one LAN port on one router to another LAN port on
another LAN port, your DHCP will get all messed up. BUT, if you connect one WAN port
to a LAN port on the other router, your DHCP will be fine. Look at it this way: your LAN
is a HUB/SWITCH and acts as one network card. Your WAN port sits on another network
card. As long as they are not "jumped" (cable going from WAN to LAN on same router)
they are two entirely different networks. They don't listen to outside DHCP, only Inside.
3) Your LAN side will use your WAN side as a gateway. So, you should have a settings option that calls for a setup of your LAN side, or your regular IP address for your router on the inside. So, that address will be the gateway. I wouldn't set it to 0.0.0.0. it's not a valid IP Address.
4) The LAN configuration is up to you. If you want, your outside IP (your WAN) needs to be the outside network, that is nonnegotiable. The LAN, however is whatever you want! (granted it is a valid TCP/IP address (let's say 10.10.10.2).
5) Leave the Old router the way it is.
6) That should be it!

Lemme know it this helps. I could really use the feedback.

I think that you want to use the regular ports on the routers to tie them together. The ports will auto-negotiate. Use the WAN port of the first router for the DSL connection, and let the first router perform all of the NAT and DHCP service.

Well I have sorted it out now, but not the way I thought I had to.
I tested to connect the routers via the LAN ports on both of them
and yes I could access the router but what was more surprising was that I was able to send over the Linux system to it.
I had read that the WAN port had to be configured for it to work and I assumed that it was because the system had to be send via the WAN port, the Internet.
but that wasn't the case, but I did notice that when I hadn't configured the WAN port for instance when i had reseted the router it didn't work.

I haven't tested if I can connect anything to the LAN ports on the new router but that wasn't the point so I'm happy with my 195 MHz MIPS Linux system
I have even manage to port my programs to it.

I guess I could use it like a server for my own net games and apps.

I still think it should be possible to connect them via the WAN port, isn't the whole Internet routed that way?

The "Internet" port is intended to provide the connection to a Cable or DSL modem. By default, the router will be a DHCP client on this port and provide a DHCP client for clients on the other ports. Also, either NAT or routing is provided between the Internet port and the switch ports. Unless you have your network divided with different subnets and need the router to connect computers on the two network segments, using the second router as another network switch would probably work best. A different Linksys Cable/DSL router (without wireless ) has a WAN port that connects to the modem, as well as an uplink port to connect to another switch/router. The uplink port is simply a "II" (straight through) rather than an "X" connection to the highest numbered switch port. For your router, this extra port isn't needed because it is auto-negotiating.

You might want to check the Linksys website. An upgrade of the firmware may allow you to tie together the two routers using the wireless connection.