I know there other methods to ssh tunneling, but this is a simple way to use ssh to access other systems on the LAN your ssh'ing to. Add something like below to your ~/.ssh/config file on the client side.
Host dward.us Port 443 user david LocalForward 8080 10.1.1.2:80 Localforward 8081 10.1.1.1:80 LocalForward 8082 p2002l:80 LocalForward 8025 10.1.1.1:25 LocalForward 8143 10.1.1.1:143
So I can ssh to a PC in my house using domain name dward.us and then with these settings, I can access a computer with IP 10.1.1.2 and through port 80 (http) using localhost port 8080. Very easy and very handy.