make linux RH as router/gateway

dear all experts
I'm on my way to make my linux PC (with 2 NICs) be a router/gateway for my LANs to get through internet, and also from that linux PC I can simulate network conditions like latency or bandwidth shortage.

Here is my setup for linux

eth0 - connected directly to my ISP - IP: 209.172.108.16 - Gateway = 209.172.108.1 Sub= 255.255.255.224, primary and secondary = 209.81.59.2/209.81.9.151

eth1 - connected to a switch (that connects with 2 windows servers) - IP: 192.168.1.1, Sub = 255.255.255.0, I do not set gateway for this interface.

Here is my setup for 1 windows server: IP = 192.168.1.2 Gateway = **192.168.1.1**, sub = **255.255.255.0**.

I was able to ping from windows to linux and vice versa. But, I could not get to the internet from windows server.
I believe that I have to set sth with IPTABLES, is this correct?

And, is it possible to create a linux router/gateway such that I can allow traffic like HTTP, MySQL, FTP , email to my 2 windows servers??

Thanks so much!!
I'm really appreciated your helps