An SSH SOCKS proxy is a good way to securely break through a restrictive firewall. Like say, checking GMail at work, or posting protest videos to YouTube from inside Iran. But it takes a bit of setting up: first open Terminal to start up your SSH connection, specifying -ND [socks port], and then updating the settings in Network Preferences to use the SOCKS proxy. A bit of a chore to have to do regularly.
Secret Socks is a (free and open source) little program that does all this for you. Just type in your account password and click Connect. It automatically updates your network settings, and will change it back automatically after you disconnect.
And if that's not good enough, it comes packaged with a cutting-edge SSH client (obfuscated-openssh) that defeats deep packet inspection. Your SOCKS proxy will be kept secret from programs looking out for encrypted connections. Just something extra in case your boss/government is trying to block SSH connections. Of course, your SSH server will also need to support obfuscated-openssh for that to work. Otherwise, just use regular SSH. I've only tested this on Leopard.
Mac OS X Hints
http://hints.macworld.com/article.php?story=20090716173730232