Setting up a home gateway/router

[csanyipal@gmail.com]

Hi,

I wish to set up my home headless power pc box as a gateway/router ( GW ).
I can connect to it with SSH only.

Before, I set up this GW to get an IP address from my ISP with
dhcp.client.

Now, I ask a static IP address for this GW and don't know how to setup
eth0 interface so I can connect to Internet from this GW and to forward
Internet connection to my LAN.

My ISP
  |
  --- eth0 ( GW ) --- eth1
                        |
                        LAN

This is my home network that I want to set up.

The state of this setup so far is that that I can SSH into GW only, but
can't reach the Internet, and from LAN I can't reach Internet too.

Can I get advices how to setup my home network?

--
Regards, from Paul