Setup an SSH tunnel on Mac OS X

There are some apps available to setup an SSH tunnel on OS X, but you can do it very easily in the terminal.

Just start a SOCKS web proxy using this SSH command:

$ ssh -D 8080 -C -N username@myserver.com -p 22

Once your proxy is running you must tell OS X to use this web proxy. Go to System preferences, Network, Advanced. Open the Proxies tab and select SOCKS-proxy.
Set the server: 127.0.0.1, set the port: 8080. Save and apply the settings, and everything should work!