Network

Proxy and Reverse Proxy

 * http://en.wikipedia.org/wiki/Proxy_server
 * http://en.kioskea.net/contents/lan/proxy.php3

SSH

 * http://www.mikeash.com/ssh_socks.html

Software

 * http://www.raynersoftware.com/netshade/
 * http://www.charlesproxy.com/